Power tool

ABSTRACT

A power tool, such as an oscillating multi-tool, is configured to drive a tool accessory in an oscillating manner. The power tool includes a motor, and a spindle supported to be rotatable around a driving axis and configured to pivotally oscillate the tool accessory, which is removably mounted on the spindle, using power generated by the motor. An inner housing of the power tool houses the motor and the spindle, and has at least one airflow inlet and at least one airflow outlet. An outer housing of the power tool houses the inner housing and is elastically connected to the inner housing via at least one elastic member to be movable relative to the inner housing. A partition is disposed between the at least one inlet and the at least one outlet. The partition divides a space defined between the inner and outer housings into first and second airflow spaces.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to Japanese patent applicationNos. 2019-215842, 2019-215843 and 2019-215844, all of which were filedon Nov. 28, 2019, and to Japanese patent application No. 2020-120254filed on Jul. 13, 2020. The contents of all of the foregoingapplications are hereby fully incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a power tool that is configured todrive (pivot) a tool accessory in an oscillating manner to therebyperform an operation, such as cutting, sanding, scraping, etc., on aworkpiece.

BACKGROUND

Known power tools (e.g., oscillating multi-tools, which are also knownin the power tool field as “multi-tool”) are configured to drive a toolaccessory coupled to a spindle in a pivotal oscillating manner within aspecified angle range. In some of these known oscillating multi-tools,the spindle and the tool accessory have complementary contact surfacesthat are inclined (oblique) with respect to a rotational axis of thespindle for the purpose of reliably absorbing torque applied to the toolaccessory.

SUMMARY

In one aspect of the present disclosure, a power tool is configured todrive (pivot) a tool accessory in an oscillating manner. The power toolmay include, e.g., a housing, a spindle, a clamp shaft (or clampingshaft), a first biasing member (e.g., a spring), an engagement member(e.g., one or more chuck jaws), a first holding member (e.g., a collar),a manually operable member (e.g., a manually operable lever) and apush-down member or pusher. The spindle is preferably hollowcylindrical. The spindle is supported by the housing to be rotatable(pivotable) around a driving axis that defines or is parallel to anup-down direction of the power tool. A tool mounting part or toolmounting surface is defined at the lower end portion of the spindle. Theclamp shaft is coaxially disposed with the spindle (e.g., within orinside the hollow interior of the spindle) and is configured to beremovable (separable) from the spindle. The first biasing member isconfigured to bias the clamp shaft upward toward a clamp position (orclamping position), in (at) which a lower end portion (e.g., a clampinghead) of the clamp shaft and the tool mounting part clamp the toolaccessory therebetween. The engagement member is configured to engagewith and/or press against the clamp shaft and thereby hold the clampshaft in the clamp position. The first holding member holds theengagement member such that the engagement member is movable (relativeto the first holding member) between a first (vertical) position and asecond (vertical) position in the up-down direction. When the engagementmember is in the first position, the engagement member is engageablewith and/or pressed against the clamp shaft and is immovable in a radialdirection that is perpendicular to the driving axis. When the engagementmember is in the second position, the engagement member is movable inthe radial direction. The manually operable member is configured to beexternally manipulated by a user. The push-down member is movable in theup-down direction relative to the spindle. The tool mounting part mayhave a first inclined surface (e.g., a truncated cone-shaped surface)that is inclined (oblique) relative to the driving axis and againstwhich a second inclined surface (e.g., a complementary truncatedcone-shaped surface) of the tool accessory is pressed when the toolaccessory is clamped. In response to a manual unclamping operation beingperformed on the manually operable member by the user, a first one ofthe engagement member or the first holding member is moved downwardrelative to the spindle and relative to a second (i.e. other) one of theengagement member or the first holding member. The engagement member isconfigured to move from the first position to the second positionrelative to the first holding member in response to the manualunclamping operation. The first one of the engagement member and thefirst holding member is configured to push down the tool accessory viathe push-down member in the process of moving downward.

In such a power tool, the first one of the engagement member and thefirst holding member is moved downward relative to the second one inresponse to the manual unclamping operation. Thus, the engagement membermoves to the second position and is allowed to be disengaged (released,separated) from the clamp shaft. Further, the first one of theengagement member and the first holding member pushes down the toolaccessory via the push-down member in the process of moving downward.Therefore, even if the tool accessory sticks (adheres) to the toolmounting part along the first and second inclined surfaces, the user caneasily remove the tool accessory from the spindle together with theclamp shaft, by simply performing the unclamping operation on themanually operable member.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing a representative, non-limitingoscillating multi-tool (multi-tool) according to one exemplaryembodiment of the present teachings, wherein a lever is in a frontposition.

FIG. 2 is a sectional view of the oscillating multi-tool.

FIG. 3 is a sectional view taken along line III-III in FIG. 2 (wherein atool accessory is omitted for the purposes of clarity).

FIG. 4 is a perspective view of an inner housing as viewed from above.

FIG. 5 is a perspective view of the inner housing as viewed from below.

FIG. 6 is a partial, enlarged view of FIG. 2 .

FIG. 7 is a partial, enlarged view of FIG. 6 .

FIG. 8 is a sectional view taken along line VIII-VIII in FIG. 7 .

FIG. 9 is a sectional view corresponding to FIG. 7 , wherein the leveris in an upper position.

FIG. 10 is a sectional view corresponding to FIG. 8 , wherein the leveris in the upper position.

FIG. 11 is a bottom view of the oscillating multi-tool, wherein a lowershell has been removed therefrom.

FIG. 12 is a sectional view taken along line XII-XII in FIG. 6 .

FIG. 13 is a perspective view of the oscillating multi-tool, wherein anupper shell has been removed therefrom.

FIG. 14 is a plan view of the oscillating multi-tool, wherein the uppershell has been removed therefrom.

FIG. 15 is a sectional view, corresponding to FIG. 8 , for illustratingan arrangement of a lever and a rotary shaft according to a modifiedembodiment of the present teachings.

FIG. 16 is an exploded, perspective view of the lever and the rotaryshaft of the modified embodiment.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Oscillating tools (multi-tool) 1 according to non-limiting,representative embodiments of the present teachings will now bedescribed. The oscillating multi-tools 1 shown in the Figures areexemplary examples of an electric power tool that is configured toperform an operation on a workpiece (not shown) by driving (pivoting) atool accessory 91 in an oscillating manner within a specified angularrange, e.g., that is less than 5°.

First, the general structure of the oscillating multi-tool 1 shown inFIGS. 1-14 is described. As shown in FIGS. 1 and 2 , the oscillatingmulti-tool 1 has an elongate housing (also referred to as a tool body)10. An elongate spindle 5 and a motor 41, which serves as a drivingsource, are housed in one end portion of the housing 10 in itslongitudinal direction. The spindle 5 is arranged such that alongitudinal axis of the spindle intersects (more specifically, at leastsubstantially orthogonally intersects) a longitudinal axis of thehousing 10. One (lower) axial end portion of the spindle 5 protrudesfrom the housing 10 and is exposed outside of the housing 10. This loweraxial end portion of the spindle 5 forms (defines) a tool mounting part51, to (on) which the tool accessory 91 is removably mounted. Further, abattery (battery pack, battery cartridge) 93 for supplying electricpower to the motor 41 is removably mounted to the other end portion ofthe housing 10 in the longitudinal direction. In the oscillatingmulti-tool 1, the spindle 5 is driven about a driving axis A1 with arotary (pivotal) oscillating motion within a specified angle range,using power generated by the motor 41, and thereby oscillates the toolaccessory 91 in an oscillation plane P.

For the sake of convenience in the following description, the directionsof the oscillating multi-tool 1 are related in the following manner. Anextension direction of the driving axis A1 is defined as an up-downdirection. In the up-down direction, the side on which the tool mountingpart 51 of the spindle 5 is located is defined as a lower side of theoscillating multi-tool 1, while the opposite side is defined as an upperside of the oscillating multi-tool 1. A direction that is orthogonal tothe driving axis A1 and that corresponds to the longitudinal directionof the housing is defined as a front-rear direction of the oscillatingmulti-tool 1. In the front-rear direction, the side of one end portionof the housing 10 in which the spindle 5 is housed is defined as a frontside of the oscillating multi-tool 1, while the side of the other endportion to (on) which the battery 93 is mounted is defined as a rearside of the oscillating multi-tool 1. Further, a direction that isorthogonal to both the up-down direction and the front-rear direction isdefined as a left-right direction.

The structure of the oscillating multi-tool 1 is now described infurther detail.

First, the housing 10 is described. As shown in FIGS. 1 to 3 , thehousing 10 of this embodiment is configured as a so-calledvibration-isolating housing. The housing 10 includes an elongate outerhousing 2, which forms an outer shell of the oscillating multi-tool 1,and an elongate inner housing 3, which is housed in (surrounded by) theouter housing 2.

In this embodiment, the outer housing 2 is formed by connecting an uppershell (upper housing half) 27, a lower shell (lower housing half) 28 anda switch holder 20 that are each formed separately from each other. Eachof the upper shell 27, the lower shell 28 and the switch holder 20 is amember (structure, component) that is integrally molded from syntheticresin/polymer. Although not shown in detail, the outer housing 2 isformed by fitting (mating) the upper shell 27 and the lower shell 28together in the up-down direction with the switch holder 20 disposedtherebetween and connecting them by screws at multiple positions.

In relation to the front-rear direction, the outer housing 2 includes afront part 21, a rear part 23 and a central part 22 connecting the frontpart 21 and the rear part 23.

The front part 21 has a generally rectangular box-like shape. A frontpart 30 of the inner housing 3 is disposed in the front part 21. A lever77 is rotatably (pivotably) supported by (at) an upper front end portionof the front part 21. The lever 77 is a manually operable member(manipulation member) for securing (locking, clamping) the toolaccessory 91 and for releasing (unlocking, unclamping) the toolaccessory 91 via a lock mechanism 6, which will be described below (seeFIG. 7 ). Further, an opening is provided in an upper wall of the frontpart 21. A slide operation (manipulation) part (slide switch or switchknob) 294 is exposed to the outside through this opening, so that a usercan manipulate (slide) the operation part 294. The operation part 294 isa manually operable (slidable) member (manipulation member) forswitching ON and OFF a switch 29 for starting the motor 41.

The rear part 23 has a tubular shape having a sectional area increasingtoward the rear. An elastic connection part 37 and a rear part 38 of theinner housing 3 are disposed within the rear part 23.

The central part 22 has a tubular shape. The central part 22 linearlyextends in the front-rear direction. The central part 22 forms a grippart configured to be held by the user. Therefore, the central part 22is narrower (i.e. has a smaller diameter or cross-section) than thefront part 21 and the rear part 23 so as to be easy to hold (grasp) withone hand.

As shown in FIGS. 2 to 6 , in this embodiment, the inner housing 3 isformed by connecting a metal housing 301 and a plastic housing 302 thatare formed separately from each other. The metal housing 301 is a single(integral) metal member (structure, component), i.e. there are no seamsbetween the various portions thereof; it may be, e.g., a cast metalpart, a machined metal part, or a 3-D printed metal part. The plastichousing 302 is formed by connecting a left shell 303 and a right shell304 that are formed of synthetic resin/polymer. The inner housing 3 isformed by connecting the left shell 303, the right shell 304 and themetal housing 301 by screws at multiple positions, with a rear endportion (a connecting part 321 to be described below) of the metalhousing 301 held between the left shell 303 and the right shell 304 inthe left-right direction.

Further, in relation to the front-rear direction, the inner housing 3includes the front part 30, an extending part 36, the elastic connectionpart 37 and the rear part 38.

The front part 30 houses the spindle 5, the motor 41 and a transmittingmechanism (rotation-to-oscillating motion converting mechanism) 45. Thefront part 30 includes a first housing part 31, a second housing part32, the connecting part 321, a third housing part 33 and a cover part35. The metal housing 301 is formed by the above-mentioned parts of thefront part 30 other than the cover part 35 (that is, the metal housing301 is formed by the first housing part 31, the second housing part 32,the connecting part 321 and the third housing part 33). The plastichousing 302 is formed by the cover part 35, the extending part 36, theelastic connection part 37 and the rear part 38, which will be describedbelow.

The first housing part 31 houses the spindle 5. The first housing part31 has a generally circular hollow cylindrical shape and extends in theup-down direction. The first housing part 31 has an open upper end,which is covered with (by) a cover 311. The cover 311 is fixed to thefirst housing part 31 with (by) pins. The second housing part 32 housesthe motor 41. The second housing part 32 has a generally circular hollowcylindrical shape having a larger diameter than the first housing part31. The second housing part 32 is disposed behind the first housing part31. Further, the second housing part 32 is shorter than the firsthousing part 31 in the up-down direction. A lower end of the secondhousing part 32 is located above a lower end of the first housing part31. The connecting part 321 is a plate-like portion that extends from arear end of the second housing part 32 and projects rearward. Theconnecting part 321 is disposed between the left shell 303 and the rightshell 304, and is fixed to the left shell 303 and the right shell 304 byscrews. The third housing part 33 houses the transmitting mechanism 45.The third housing part 33 is disposed behind the first housing part 31and under the second housing part 32. The third housing part 33communicates with the first housing part 31 and the second housing part32. The cover part 35 covers an open upper end of the second housingpart 32.

The extending part 36 is a hollow cylindrical part that is connected toa rear end portion (specifically, to the second housing part 32) of thefront part 30 and extends rearward. The length of the extending part 36in the front-rear direction is approximately equal to the length of thecentral part (grip part) 22 in the front-rear direction. The extendingpart 36 is thus generally entirely disposed in the central part 22. Theextending part 36 has an open rear end. In other words, the rear end ofthe extending part 36 defines an opening.

The elastic connection part 37 extends rearward from a rear end of theextending part 36 and connects the extending part 36 and the rear part38 such that the extending part 36 and the rear part 38 are movablerelative to each other. The elastic connection part 37 includes aplurality of elastic ribs 371 that connect the extending part 36 and therear part 38 in the front-rear direction. In this embodiment, four suchelastic ribs 371 are arranged spaced apart from each other around alongitudinal axis of the inner housing 3 extending in the front-reardirection. The elastic ribs 371 are shaped to be easily deformable andare also formed of a material having a lower elastic modulus than theother portions of the inner housing 3. The elastic ribs 371 can thusreduce (attenuate) transmission of vibration, which is generated in thefront part 30 during operation, to the rear part 38 by elasticallyabsorbing the vibration.

The rear part 38 has a generally rectangular box-like shape. The rearpart 38 is disposed within the rear part 23 of the outer housing 2 asdescribed above. A gap is formed between the rear part 23 and an outerperipheral surface of the rear part 38.

The outer housing 2 and the inner housing 3 are elastically connectedwith each other so as to be movable relative to each other. Thestructures for elastically connecting the outer housing 2 and the innerhousing 3 will be described in detail below.

The structures (elements) disposed within the inner housing 3 are nowdescribed in the order of the front part 30, the rear part 38, theelastic connection part 37 and the extending part 36.

First, the structures (elements) disposed within the front part 30 aredescribed. As shown in FIG. 6 , the front part 30 houses the spindle 5,the motor 41, the transmitting mechanism 45, a clamping mechanism 60 anda push-down mechanism 67.

The spindle 5 is now described. As shown in FIG. 7 , the spindle 5 is anelongate hollow member having a generally circular cylindrical shape. Inthis embodiment, the spindle 5 is supported by two bearings 501, 502 tobe rotatable around the driving axis A1. The bearings 501, 502 are heldin a lower portion of the first housing part 31. As described above, thelower end portion of the spindle 5 is configured as the tool mountingpart 51, to (on) which the tool accessory 91 is removably mounted.

In this embodiment, the tool mounting part 51 is shaped like a flangeprotruding radially outward relative to the driving axis A1. The toolmounting part 51 has an inclined surface (oblique surface) 513 that isinclined (oblique) in a direction intersecting the driving axis A1. Morespecifically, a recess 511, which is indented upwardly, is formed in(on) a lower end portion of the tool mounting part 51. The inclinedsurface 513 is a portion of a surface that defines the recess 511, andis inclined downward and away from the driving axis A1 (i.e. radiallyoutward). The portion of the tool mounting part 51 having the inclinedsurface 513 optionally may be formed, e.g., as a truncated cone. All ofthe tool accessories 91 (such as, e.g., a blade, a scraper, a grindingpad and a polishing pad) that are attachable to the oscillatingmulti-tool 1 of this embodiment have a protruding part 911 that isconfigured to be fitted in (mated with) the recess 511. A portion of anupper surface of the tool accessory 91 that defines the protruding part911 is formed as an inclined surface 913, which conforms to the inclinedsurface 513. That is, the portion of the tool accessory 91 having theinclined surface 913 may also be formed, e.g., as a truncated cone thatis complementary (matching) to the truncated cone of the tool mountingportion 51 so that the two truncated cones can be fit or mated togetherto form a line contact (circular line contact) between the two matedparts. In this embodiment, the tool accessory 91 is clamped between thetool mounting part 51 and a clamp head (clamping head) 615 of a clampshaft (clamping shaft) 61, which will be described below, and is therebysecured (fixed) to the spindle 5, in a state in which the inclinedsurface 913 is in abutment with the inclined surface 513. Fixing thetool accessory 91 to the spindle 5 will be described in detail below.Further, a recess 515 is formed in a central portion of the recess 511.The recess 515 is recessed further upward from the recess 511 and has acircular cross-section.

The motor 41 is now described. The motor 41 is preferably a brushless DCmotor. As shown in FIG. 6 , the motor 41 has a stator, a rotor disposedwithin the stator, and an output shaft (rotary shaft) 415 that isconfigured to rotate together with the rotor. The motor 41 is housed inthe second housing part 32 such that a rotational axis A2 of the outputshaft 415 extends in parallel, or at least substantially in parallel, tothe driving axis A1 (i.e. in the up-down direction). The output shaft415 protrudes downward from the rotor.

The transmitting mechanism 45 is now described. The transmittingmechanism 45 is configured to convert rotary motion of the output shaft415 into rotary (pivotal) oscillating motion of the spindle 5 within aspecified angle range around the driving axis A1. As shown in FIG. 6 ,the transmitting mechanism 45 includes an eccentric shaft 451, a drivebearing 456, and an oscillating arm 458.

The eccentric shaft 451 is coaxially connected with the output shaft 415of the motor 41. The eccentric shaft 451 is fixed to an outer peripheryof the output shaft 415. The eccentric shaft 451 extends downward into alower end portion of the third housing part 33. The eccentric shaft 451is rotatably supported by two bearings 452, 453, which are respectivelyheld in a lower end portion of the second housing part 32 and in a lowerend portion of the third housing part 33. The eccentric shaft 451 has aneccentric part (cam) 454 that is eccentric to the rotational axis A2. Aninner ring of the drive bearing 456 is fixed around the eccentric part454. The oscillating arm 458 operably connects the drive bearing 456 andthe spindle 5. The oscillating arm 458 extends across the first housingpart 31 and the third housing part 33. Although not shown in detail,because it is a well-known structure, one end portion of the oscillatingarm 458 is annular-shaped and fixed around an outer periphery of thespindle 5 between the bearings 501, 502. The other end portion of theoscillating arm 458 is bifurcated (forked) and its two ends are disposedto abut on the left side and the right side, respectively, of an outerperipheral surface of an outer ring of the drive bearing 456.

When the motor 41 is driven, the eccentric shaft 451 rotates togetherwith the output shaft 415. In response to rotation of the eccentricshaft 451, a center of the eccentric part 454 moves (orbits) around therotational axis A2 and thus the drive bearing 456 also moveseccentrically around the rotation axis A2, which causes the oscillatingarm 458 to oscillate within the specified angle range about the drivingaxis A1 of the spindle 5. The spindle 5 is thus driven with a rotary(pivotal) oscillating motion within the specified angle range around thedriving axis A1 in response to oscillating movement of the oscillatingarm 458. As a result, the tool accessory 91 mounted to (on) the spindle5 oscillates about the driving axis A1 in the oscillation plane P, whichenables a processing operation to be performed on a workpiece using theoscillating multi-tool accessory 91.

A fan 43 is fixed to an upper end portion of the eccentric shaft 451.The fan 43 of this embodiment is a centrifugal fan. The fan 43 isconfigured to draw air from above (in the direction of (in parallel to)the rotational axis A2) and feed (push) the air radially outward, whilerotating around the rotational axis A2 when the motor 41 is driven.Thus, rotation of the fan 43 generates an air flow for cooling the motor41 within the housing 10. Airflow paths within the housing 10 will bedescribed in detail below.

The clamping mechanism 60 is now described. The clamping mechanism 60 isconfigured to secure (fix) the tool accessory 91 to the tool mountingpart 51 such that the tool accessory 91 rotates (pivots back and forth)together with the spindle 5. As shown in FIGS. 7 and 8 , in thisembodiment, the clamping mechanism 60 includes a clamp shaft (holdingbolt) 61, a clamp spring 65 and a lock mechanism (latching mechanism) 7.

The clamp shaft 61 is an elongate member having a generally rod-likeshape. The clamp shaft 61 is removably inserted through (into) thespindle 5 to be coaxial with the spindle 5. The clamp shaft 61 has around rod-like shaft part 611 and a flange-like clamp head 615. Theshaft part 611 extends along (coincides with) the driving axis A1. Theclamp head 615 is connected to a lower end portion of the shaft part611. Further, a groove part 612 is formed in (at) an upper end portionof the shaft part 611. The groove part 612 has a plurality of groovesformed around the entire circumference of the clamp shaft 61 andarranged in the up-down direction.

The clamp spring 65 is a biasing member that biases the clamp shaft 61upward relative to the spindle 5 and thereby applies to the clamp shaft61 a clamping force for clamping the tool accessory 91. In thisembodiment, the clamp spring 65 is configured to bias the clamp shaft 61upward via the lock mechanism 7 (specifically, a holder 73 and clampmembers 71) described below. More specifically, the clamp spring 65 is acompression coil spring. The clamp spring 65 is disposed in a compressedstate (i.e. in a loaded state) between a spring receiving member (springseat) 57 and the holder 73 that will be further described below. Thespring receiving member 57 is disposed on an upper end of the spindle 5,such that the spring receiving member 57 rotates together with thespindle 5.

The lock mechanism 7 is configured to hold (lock) the clamp shaft 61 in(at) a clamp position (or clamping position) (shown in FIGS. 7 and 8 ),in (at) which the clamp shaft and the tool mounting part 51 are capableof clamping the tool accessory 91. The lock mechanism 7 is disposedabove the spindle 5 within the first housing part 31. In thisembodiment, the lock mechanism 7 includes a pair of clamp members(clamping members or chuck jaws) 71, the holder 73, an elastic ring 718and a collar 75.

The two clamp members 71 are arranged to face each other across thedriving axis A1. A radially inner surface of each clamp member 71 iscurved to conform to an outer peripheral surface of the shaft part 611.A ridge part 717 is formed on this curved inner surface of each clampmember 71. The ridge part 717 has a plurality of ridges extending in thecircumferential direction and arranged in the up-down direction. Theridges of the ridge parts 717 of the two clamp members 71 are configuredto engage (mesh) with the grooves of the groove part 612 of the clampshaft 61. Upper and lower end portions of each clamp member 71 protruderadially outward, compared to a radially narrower central portion of theclamp member 71. In other words, the central portion of each clampmember 71 in the up-down direction defines a circumferentially-extendinggroove that extends around the entire circumference of the two clampmembers 71.

The holder 73 is configured to hold the clamp members 71 such that theclamp members 71 are movable in the radial direction relative to (i.e.perpendicular to) the driving axis A1, but are not movable in theup-down direction relative to the holder 73. In this embodiment, theholder 73 is formed as a circular cylindrical member having a largerdiameter than the shaft part 611 of the clamp shaft 61 as a whole. Theholder 73 has an insertion hole 731 and a pair of holding recesses 733.

The insertion hole 731 is a blind hole that extends upward from a lowersurface of the holder 73 along the driving axis A1 and has a closedupper end. The insertion hole 731 has a circular cross-section and has adiameter slightly larger than the shaft part 611 of the clamp shaft 61.That is, the inner diameter of the insertion hole 731 is sized to permitthe upper end portion of the shaft part 611 to be inserted into theinsertion hole 731.

The two holding recesses (slots) 733 are formed in a central portion ofthe holder 73 in the up-down direction. The holding recesses 733 eachextend radially inward (toward the driving axis A1) from the outerperipheral surface of the holder 73. The radially inner edge of each ofthe holding recesses 733 communicates with the insertion hole 731. Eachholding recess 733 has a shape that conforms to one of the clamp members71. The clamp members 71 are disposed within the holding recesses 733,respectively, so as to be movable in the radial direction relative tothe holder 73.

More specifically, each of the clamp members 71 is movable in the radialdirection between an engagement position (shown in FIG. 7 ), which iscloser to the driving axis A1, and a disengagement position (shown inFIG. 9 ), which is farther from the driving axis A1 (i.e. thedisengagement position is located radially outward of the engagementposition). When the clamp members 71 are in their respective engagementpositions, the ridge parts 717 of the clamp members 71 are engaged withthe respective grooves of the groove part 612 of the clamp shaft 61.Further, when the clamp members 71 are in their engagement positions,outer peripheral surfaces of the clamp members 71 are each arrangedsubstantially flush with an outer peripheral surface of the holder 73 soas not to protrude radially outward from the holding recesses 733. Onthe other hand, when the clamp members 71 are in their respectivedisengagement positions, the ridge parts 717 are not engaged orengageable with the groove part 612. Further, when the clamp members 71are in their respective disengagement positions, the outer peripheralsurfaces of the clamp members 71 each slightly protrude radially outwardfrom the holding recess 733, i.e. radially outward of the outerperipheral surface of the holder 73.

Further, the lower end portion of the holder 73 has a flange-like springreceiving part (spring seat or spring abutment surface) 735 thatprotrudes radially outward. A lower surface of the spring receiving part735 is in abutment with an upper end portion of the clamp spring 65.Further, a lower surface of a lower end central portion (an annular partsurrounding the insertion hole 731) of the holder 73 serves as anabutment part 737, which abuts on a push-down sleeve (pusher) 671 whenan unclamping operation is performed, which will be described in detailbelow.

The elastic ring 718 is fitted in the grooves that are respectivelyformed in the central portions of the outer peripheral surfaces of theclamp members 71. The elastic ring 718 biases the clamp members 71radially inward toward their respective engagement positions. Theelastic ring 718 of this embodiment is an annular member formed ofrubber or another elastomer.

The collar 75 is a hollow circular cylindrical member. The collar 75holds (surrounds) the holder 73 and the clamp members 71 such that theholder 73 and the clamp members 71 are linearly movable relative to thecollar 75 along the driving axis A1 (i.e. in the up-down direction). Theholder 73 is disposed inside the collar 75 to be slidable in the up-downdirection along an inner peripheral surface of the collar 75. The collar75 is supported to be immovable in the up-down direction relative to theinner housing 3, and to be rotatable around the driving axis A1. Morespecifically, the collar 75 is rotatably supported by a bearing 751 thatis disposed around the collar 75 and held within an upper end portion ofthe first housing part 31. Because the collar 75 is disposed above thespindle 5 in the first housing part 31, rather than within the spindle5, assembly of the collar 75 is facilitated. The collar 75 may bedesigned, e.g., as a linear slide bearing or sleeve bushing thatsupports linear movement of the holder 73 while permitting both linearand radial movement of the clamp members 71.

More specifically, in this embodiment, the collar 75 is configured toselectively prevent (block) and allow radial movement of the clampmembers 71 from the engagement positions to the disengagement positions,depending on the position of the collar 75 relative to the clamp members71 in the up-down direction. In other words, each of the clamp members71 is movable in the up-down direction relative to the collar 75 betweena position (hereinafter referred to as a lock position) in which theclamp member 71 is not allowed to move from the engagement position anda position (hereinafter referred to as an unlock position) in which theclamp member 71 is allowed to move in the radial direction from theengagement position to the disengagement position.

More specifically, the collar 75 has approximately the same innerdiameter as the outer diameter of the upper portion of the holder 73. Anannular groove 753 is formed in a central portion of the collar 75 inthe up-down direction. The annular groove 753 is recessed radiallyoutward from the inner peripheral surface of the collar 75. Therefore,as shown in FIG. 7 , at a position where the outer peripheral surfacesof the two clamp members 71 (more specifically, the outer peripheralsurfaces of the upper and lower end portions thereof) abut on thesmaller inner diameter portion of the inner peripheral surface of thecollar 75 (other than the groove 753, which is a larger inner diameterportion of the inner peripheral surface of the collar 75), the clampmembers 71 are blocked from moving radially outward from the engagementposition. Thus, the clamp members 71 are located and maintained (held)in the lock position (engagement position). On the other hand, as shownin FIG. 9 , at a position where the upper end portions of the clampmembers 71 face (oppose) the groove 753 and the lower end portion of thecollar 75 faces (oppose) the groove formed in the outer peripheralportions of the clamp members 71 (and thus oppose the elastic ring 718),the clamp members 71 are movable (are not blocked from moving) radiallyoutward from the engagement position to the disengagement position.Thus, the clamp members 71 are located in the unlock position. In thisembodiment, the clamp members 71 are held by the holder 73 as describedabove. Therefore, the clamp members 71 are movable in the up-downdirection and in the radial direction relative to the collar 75 in astable manner.

The positional relation between the clamp members 71 and the collar 75in the up-down direction changes in response to manual operation(turning) of the lever 77, which will be described in detail below.

The push-down mechanism 67 is now described. The push-down mechanism 67is configured to push down the tool accessory 91 relative to the spindle5 in response to operation of the clamping mechanism 60 (specifically,in response to downward movement of the holder 73). As shown in FIGS. 7and 8 , in this embodiment, the push-down mechanism 67 includes apush-down sleeve (pusher) 671 that is movable in the up-down directionrelative to the spindle 5, and a biasing spring 675 that biases thepush-down sleeve 671 upward relative to the spindle 5.

The push-down sleeve 671 is inserted through (into) the spindle 5 to becoaxial with the spindle 5. Further, the push-down sleeve 671 isconfigured to allow the clamp shaft 61 to be inserted therethrough.Thus, the push-down sleeve 671 is disposed between the spindle 5 and theclamp shaft 61 in the radial direction.

More specifically, in the present embodiment, the push-down sleeve 671is an elongate hollow circular cylindrical member (shaft). The push-downsleeve 671 has an outer diameter that is approximately equal to theinner diameter of the spindle 5 and an inner diameter that isapproximately equal to the diameter of the shaft part 611. The push-downsleeve 671 is longer than the spindle 5, and an upper end portion of thepush-down sleeve 671 protrudes upward from the spindle 5. The clampshaft 61 is longer than the push-down sleeve 671. When the clamp shaft61 is inserted through the push-down sleeve 671, the clamp head 615 andthe groove part 612 respectively protrude from the lower end and theupper end of the push-down sleeve 671. A lower end portion of thepush-down sleeve 671 forms a large-diameter part 673 having a largerdiameter than other portions of the push-down sleeve 671. Thelarge-diameter part 673 is configured to be fitted in the recess 515formed in the lower end portion of the spindle 5. The large-diameterpart 673 has an annular flat lower end surface 674.

Although the push-down sleeve (pusher) 671 is a hollow circularcylindrical shaft in the present embodiment, it may be modified invarious ways while still performing the function of pushing down thetool accessory 91 relative to the spindle 5 (thereby breaking anyadhesion between the tool accessory 91 and the tool mounting portion 51)in response to an unclamping operation performed by the lever 77. Forexample, the push-down sleeve (pusher) 671 may instead be designed asone or more elongate bars having a first longitudinal end configured tocontact (directly or indirectly) and press the tool accessary 91 and asecond longitudinal end configured to receive a downward pressing forcegenerated when the lever 77 pivots from the clamped position to theunclamped position. The lever 77 may directly contact the secondlongitudinal end of such a pusher (elongate bar) or the force generatedby the lever 77 may be indirectly communicated to the secondlongitudinal end of such a pusher, e.g., via the holder 73 or anotherintermediate structure (member). Such a pusher may include a flange orother type of spring seat that is pressed upwardly by the biasing spring675 or by the clamp spring 65. One or more longitudinally (vertically)extending grooves may be defined in the inner surface of the spindle 5and/or in the outer surface of the clamp shaft 61 to receive theelongate bar(s) and support linear sliding movement of the pusherrelative to both the spindle 5 and the clamp shaft 61. The firstlongitudinal end of such a pusher may have a larger cross-section in theup-down direction and portions of the pusher upward of the firstlongitudinal end so that a larger surface of the pusher contacts andpresses against the tool accessory 91.

The biasing spring 675 is a compression coil spring having a smallerdiameter than the clamp spring 65. The biasing spring 675 is disposedinside the clamp spring 65. A lower end portion of the biasing spring675 is in abutment with the spring receiving member 57. Thus, the springreceiving member 57 serves as common spring receiving part (spring seat)for both the clamp spring 65 and the biasing spring 675. As a result, acompact arrangement of the clamp spring 65 and the biasing spring 675 isrealized, while preventing an increase of the number of components (partcount).

Further, an upper end portion of the biasing spring 675 is in abutmentwith a spring receiving member (spring seat or spring stop) 676. Thespring receiving member 676 is disposed above the spring receivingmember 57. The spring receiving member 676 is fitted around thepush-down sleeve 671 so as to be movable in the up-down directionrelative to the spring receiving member 57. An upper end portion of thespring receiving member 676 is held in abutment from below with aprojection formed on an outer periphery of the push-down sleeve 671.Such a structure enables the biasing spring 675 to bias the push-downsleeve 671 upward via the spring receiving member 676.

The push-down sleeve 671 is normally held in (at) an uppermost position,in (at) which a shoulder part (stepped part) of the large-diameter part673 abuts on a shoulder part (stepped part) of the recess 515 of thespindle 5. When the push-down sleeve 671 is located in (at) theuppermost position, the lower end (the lower end surface 674) of thepush-down sleeve 671 is located above the tool accessory 91 (morespecifically, above the upper surface of the protruding part 911)clamped between the tool mounting part 51 and the clamp head 615.Further, an upper end of the push-down sleeve 671 is located below thelower surface (the abutment part 737) of the holder 73.

The above-described clamping mechanism 60 and push-down mechanism 67 areconfigured to operate in response to the lever 77 being manually pivoted(turned, opened) by a user. More specifically, the positional relationof the clamp members 71 and the holder 73 with the collar 75 in theup-down direction changes in response to the manual pivoting of thelever 77. In addition, the push-down mechanism 67 also moves in responseto movement of the holder 73. The pivoting operation of the lever 77 andthe resulting operation (movements) of the clamping mechanism 60 and thepush-down mechanism 67 are now described.

First, the lever 77 is described. As shown in FIGS. 1 and 8 (see alsoFIGS. 10 and 13 ), an upper end of the lever 77 is generally U-shaped,and both upper end portions of the lever 77 are rotatably supported by(at) an upper portion of the front part 21 of the outer housing 2. Thelever 77 is manually pivotable (rotatable) between a first position(hereinafter referred to as a front position or clamping position), in(at) which a central portion of the lever 77 abuts on a front surface ofthe front part 21 as shown in FIGS. 1 and 7 , and a second position(hereinafter referred to as an upper position or unclamped position), in(at) which the central portion of the lever 77 is located above thefront part 21 as shown in FIGS. 9 and 10 . The lever 77 is fixedlyconnected to a rotary shaft (pin) 78 so that the lever 77 and the rotaryshaft 78 rotate (pivot) together around a rotational axis A3, whichextends in the left-right direction and is located above the lockmechanism 7 (the holder 73). The rotary shaft 78 is inserted through athrough hole that extends through the cover 311 of the front part 30 ofthe inner housing 3 in the left-right direction. The two end portions ofthe rotary shaft 78 are respectively connected to the two upper endportions of the lever 77 and are rotatably supported by the outerhousing 2. Therefore, the rotary shaft 78 rotates together with thelever 77 in response to manual pivoting (rotation) of the lever 77. Aneccentric part (cam part or turn block) 781, which is eccentric to therotational axis A3, is provided on a central portion of the rotary shaft78 such that the driving axis A1 intersects the eccentric part 781.

When the lever 77 is in (at) the front position, as shown in FIGS. 7 and8 , a first portion of the eccentric part 781 that has a smallerdiameter (a small-diameter part) is located spaced apart upward from theholder 73. Therefore, the rotary shaft 78 is not subjected to thebiasing force of the clamp spring 65. At this time, the clamp members 71are in their respective lock positions relative to the collar 75, andalso in their respective engagement positions and holding the clampshaft 61. The holder 73, the clamp members 71 and the clamp shaft 61 arebiased upward together, and thus the clamp shaft 61 is held in the (atits) uppermost position. Consequently, the biasing force of the clampspring 65 causes the clamp head 615 to press the tool accessory 91against the tool mounting part 51 from below and thereby secure the toolaccessory 91 to (on) the spindle 5. Thus, in this state, the clamp head615 clamps the tool accessory 91 in cooperation with the tool mountingpart 51. Accordingly, the uppermost position of the clamp shaft 61 isalso referred to as a clamp position or clamping position.

In the process of pivoting the lever 77 upward from the front positionand placing it in (at) the upper position shown in FIGS. 9 and 10 , asecond portion of the eccentric part 781 that has a larger diameter(large-diameter part) comes into contact with an upper end of the holder73 from above and thereby causes the holder 73 to move downward relativeto the spindle 5 and the collar 75 while compressing the clamp spring65. As a result, the clamping force (the force that presses the toolaccessory 91 upward against the spindle 5), which is imparted to theclamp head 615 by the clamp spring 65, is released. Accordingly, the actof pivoting the lever 77 from the front position to the upper positionis also referred to as unclamping operation.

In response to the unclamping operation, the clamp members 71 held bythe holder 73 are moved downward relative to the collar 75 and areplaced in their unlock positions. Thus, the lock mechanism 7 releases(disables) the locking of the clamp shaft 61. However, as describedabove, the two clamp members 71 are still biased toward their engagementpositions by the elastic ring 718 fitted in the respective groovesformed on the outer peripheral surfaces of the clamp members 71.Therefore, the clamp shaft 61 is temporarily held in (at) this positionby the clamp members 71 and does not disconnect from the spindle 5unless and until an external force is applied to force the clamp members71 to move (slide) radially outward from their engagement positionsagainst the biasing force of the elastic ring 718. For example, in thisstate, if the user manually pulls the clamp shaft 61 downward relativeto the spindle 5, then the clamp members 71 will be caused to move totheir disengagement positions owing to this externally applied manualforce. Therefore, the user can manually pull the clamp shaft 61 out ofthe spindle 5 to replace the tool accessory 91 while the lever 77 is in(at) its unclamped position.

Further, while the holder 73 is moving downward relative to the spindle5 in response to the unclamping operation, the abutment part 737 of theholder 73 abuts (from above) on the upper end of the push-down sleeve671 (which is located in (at) the (its) uppermost position), and thenpushes down the push-down sleeve 671 against the biasing force of thebiasing spring 675. Thus, the holder 73 performs the function of pushingdown the push-down sleeve 671, in addition to the function of holdingthe clamp members 71. While the tool accessory 91 is pressed against thetool mounting part 51 from below by the clamp head 615 with the inclinedsurface 913 in abutment with the inclined surface 513 (see FIG. 7 ) andthe tool accessory 91 is oscillated in this state, it is possible thatthe clamping pressure will cause the tool accessory 91 to stick (adhere)to the tool mounting part 51 of the spindle 5. However, when thepush-down sleeve 671 is moved (pushed) downward relative to the toolmounting part 51, the large-diameter part 673 of the push-down sleeve671 abuts on the tool accessory 91 from above and pushes down the toolaccessory 91 relative to the tool mounting part 51, thereby separatingthe tool accessory 91 from the tool mounting part 51 and eliminating(breaking) any sticking (adhesion) of the tool accessory 91 to the toolmounting part 51. In this embodiment, the lower end surface (annularflat surface) 674 of the push-down sleeve 671 comes into plane contact(surface contact), e.g., annular contact, with the upper surface of thetool accessory 91 around the shaft part 611 and pushes down the toolaccessory 91 in an evenly-balanced manner, so that the sticking of thetool accessory 91, if any, can be reliably broken.

The operation for mounting the clamp shaft 61 to (in) the spindle 5 andclamping the tool accessory 91 is basically the reverse of the operationfor removing the tool accessory 91. That is, when the lever 77 is in the(at its) upper position and the clamp members 71 are in the unlockpositions relative to the collar 75, the user inserts the clamp shaft61, with the tool accessory 91 fitted thereon, into the spindle 5 (morespecifically, into the push-down sleeve 671). The user then upwardlymoves the clamp shaft 61 to a position where an upper end of the clampshaft 61 abuts on the holder 73. In this process, the clamp members 71are first respectively moved to the disengagement positions and then arereturned to their engagement positions owing to the biasing force of theelastic ring 718. The ridge parts 717 thereby engage with the groovepart 612 such that the clamp shaft 61 is temporarily held by the clampmembers 71 owing to the radial-inward biasing force of the elastic ring718.

When the user then pivots (rotates) the lever 77 from the upper positionto the front position, the downward force that was previously applied tothe clamp spring 65 by the larger-diameter portion of the eccentric part781 (via the holder 73) in the unclamped position is released. As aresult, the clamp spring 65 biases (moves) the holder 73 and the clampmembers 71 upward relative to the collar 75. When the clamp members 71are moved to their lock positions relative to the collar 75, the clampshaft 61 also returns to the (its) clamped position.

The structures (elements) disposed within the rear part 38 are nowdescribed. As shown in FIGS. 2 to 4 , in this embodiment, a rear portionof the rear part 38 is configured as a battery mounting part 381. Thebattery mounting part 381 has an engagement structure for slidingengagement with the battery (battery pack, battery cartridge) 93, andterminals that are electrically connectable to corresponding terminalsof the battery 93. The structures of the battery mounting part 381 arewell known and therefore not described in detail here. A front portionof the rear part 38 is configured as a controller housing part 382. Thecontroller housing part 382 houses a controller 383 that includes acontrol circuit, e.g., a circuit board having a microprocessor, memory,etc. mounted thereon. The controller 383 is configured to drive(energize) the motor 41 when the switch 29 is turned ON.

The structures (elements) disposed within the elastic connection part 37are now described. As shown in FIGS. 2 to 4 , the switch holder 20 isdisposed in an internal space (a space surrounded by the elastic ribs371 in the circumferential direction) of the elastic connection part 37.The switch holder 20 is configured to hold the switch 29. Although theswitch holder 20 is disposed in the internal space of the elasticconnection part 37, the switch holder 20 is fixed to the upper shell 27and the lower shell 28 by screws, and forms part of the outer housing 2.

The structures (elements) disposed within the extending part 36 are nowdescribed. As shown in FIGS. 2 to 4 , in this embodiment, the spindle 5,the motor 41 and the transmitting mechanism 45 are disposed in the frontpart 30, and the battery mounting part 381 is disposed in or on the rearpart 38. Such an arrangement enables the number of components to bedisposed in the extending part 36 to be reduced or minimized. Althoughnot shown, only wires, which connect the controller 383 with a circuitboard attached to the motor 41, and a connecting terminal are disposedin the extending part 36, and no other components need be disposedtherein. Thus, the extending part 36 is formed narrower (i.e. theextending part 36 has a smaller diameter or section) than the front part30, the elastic connection part 37 and the rear part 38, in order toprovide an easy-to-hold dimension (periphery) for the central part (i.e.grip part) 22.

Structures for elastically connecting the outer housing 2 and the innerhousing 3 are now described. In this embodiment, the outer housing 2 andthe inner housing 3 are elastically connected to each other at multiplepositions. Specifically, elastic members are disposed between the frontpart 21 of the outer housing 2 and the front part 30 of the innerhousing 3, between the rotary shaft 78 supported by the outer housing 2and the front part 30, and between the switch holder 20 and the rearpart 38.

First, structures for elastically connecting the front part 21 of theouter housing 2 and the front part 30 or the inner housing 3 aredescribed.

As shown in FIGS. 5, 6, 11 and 12 , two recesses 335 each have acircular section and are formed in a lower wall of the front part 30.More specifically, the recesses 335 are formed in a lower wall of thethird housing part 33 that houses the oscillating arm 458 of thetransmitting mechanism 45. The recesses 335 are recessed upward from alower surface of the lower wall. The two recesses 335 are arranged sideby side in the left-right direction. Further, in the front-reardirection, the recesses 335 are located between the driving axis A1 ofthe spindle 5 and the rotational axis A2 of the output shaft 415 of themotor 41 (more specifically, between the bearing 502 and the bearing453). As shown in FIG. 12 , two cylindrical projections 215 are formedon a lower wall of the front part 21. The projections 215 protrudeupward from the lower wall of the front part 21. The projections 215respectively face (oppose) central portions of the recesses 335 of theinner housing 3.

An elastic member 11 is fitted in each of the recesses 335. Each elasticmember 11 has a hollow circular cylindrical (annular) shape. Each of theprojections 215 is fitted inside the corresponding elastic member 11such that the elastic members 11 respectively surround the entirecircumference of the projection 215. The height of each of the elasticmembers 11 is set to be larger than the depth of the recesses 335 andthe height of the projections 215, so that clearances are providedbetween the inner housing 3 and the outer housing 2 in the up-downdirection. In this manner, each hollow cylindrical elastic member 11 isdisposed between the inner housing 3 and the outer housing 2 with itsouter peripheral surface and upper end surface in contact with the innerhousing 3 and its inner peripheral surface and lower end surface incontact with the outer housing 2. In this embodiment, the elasticmembers 11 are each formed of urethane-based resin (polymer) having amicrofoam structure (also referred to as a microcellular structure).

Structures for elastically connecting the rotary shaft 78 and the frontpart 30 are now described.

As shown in FIG. 8 , left and right end portions of the rotary shaft 78are rotatably supported by left and right upper end portions of thefront part 21, respectively. The rotary shaft 78 extends through thecover 311 of the front part 30 in the left-right direction within anupper end portion of the front part 21. Recesses 313 are formed in leftand right walls of the cover 311, respectively. The recesses 313 arerecessed inward (toward the center in the left-right direction) and eachhave a circular cross-section. Two hollow circular cylindrical (annular)elastic members 13 are fitted around the rotary shaft 78. The twoelastic members 13 are respectively arranged inside of left and rightwalls of the front part 21. The elastic members 13 are respectivelyfitted in the recesses 313 with the outside portions thereof exposedfrom the recesses 313. The outside portion of each of the elasticmembers 13 is pressed against the outer housing 2 via a respectivewasher. Thus, an outer peripheral surface and an inside end surface ofeach of the elastic members 13 are in contact with the inner housing 3.An inner peripheral surface of each of the elastic members 13 is incontact with the rotary shaft 78 connected to the outer housing 2.Further, an outside end surface of each of the elastic members 13 is incontact with the outer housing 2 via the respective washers. In such acontact condition, the elastic members 13 are disposed between the innerhousing 3 and the outer housing 2. Like the elastic members 11, theelastic members 13 are also formed of urethane-based resin (polymer)having a microfoam structure.

Structures for elastically connecting the switch holder 20 and the rearpart 38 are now described.

As shown in FIG. 3 , the switch holder 20 has a generally rectangularbox-like shape. Recesses 203 are respectively formed in left and rightwalls of the switch holder 20. The recesses 203 are each recessed inward(toward the center in the left-right direction). Elastic members 15 arerespectively fitted in the recesses 203. Like the elastic members 11 and13, the elastic members 15 are also formed of urethane-based resin(polymer) having a microfoam structure. A though hole extends througheach of the elastic members 15 in the left-right direction such that theelastic members 15 have a hollow cylindrical (annular) shape. An armpart 385 protrudes forward from each of the left and right walls of therear part 38 (the controller housing part 382) of the inner housing 3. Aprojection 386 is formed on (at) a tip end portion of each arm part 385and protrudes inward (toward the center in the left-right direction). Atip end portion of each arm part 385 is in contact with an outsidesurface of the corresponding elastic member 15, and the projections 386are respectively fitted in the through holes of the elastic members 15.The elastic members 15 respectively surround the entire circumference ofeach of the projections 386. A tip end of the projection 386 is spacedapart from a bottom of the recess 203.

Owing to the above-described structures, the inner housing 3 and theouter housing 2 are movable relative to each other in all directions,including the up-down, front-rear and left-right directions, via theelastic members 11, 13, 15. Thus, the inner housing 3 and the outerhousing 2 are elastically connected to each other so as to be capable ofcoping with (absorbing, attenuating) vibrations generated in anydirection.

The largest vibration is generated in the front part 30 of the innerhousing 3 during the oscillatory driving of the tool accessory 91because the front part 30 houses the motor 41, the spindle 5 and thetransmitting mechanism 45. More specifically, the output shaft 415 andthe spindle 5 generate vibration when they are rotationally driven. Tocope with this vibration, in this embodiment, the elastic members 11elastically connect the inner housing 3 and the outer housing 2 and aredisposed between the driving axis A1 of the spindle 5 and the rotationaxis A2 of the output shaft 415 in the front-rear direction. Owing tosuch an arrangement, the elastic members 11 can cope with (absorb,attenuate) both the vibration originating at the spindle 5 and thevibration originating at the output shaft 415 and thus can effectivelyreduce transmission of vibration to the outer housing 2. Further, in theup-down direction, the elastic members 11 are disposed under the thirdhousing part 33, which houses the oscillating arm 458 of thetransmitting mechanism 45, and thus in (at) a position relatively closeto the oscillation plane P. This arrangement can reduce wobbling orrattling of the inner housing 3 within the outer housing 2 during theoscillatory driving of the tool accessory 91.

In this embodiment, because the two elastic members 11 are arranged sideby side in the left-right direction, the elastic connection has a higherdurability than in an embodiment in which only one elastic member 11 isemployed.

Further, in this embodiment, the front part 30 of the inner housing 3 iselastically connected to the outer housing 2 via the elastic members 13fitted onto the rotary shaft 78, as well as via the elastic members 11.In addition to the front part 30, the rear part 38 of the inner housing3 is elastically connected to the switch holder 20, which is part of theouter housing 2, via the elastic members 15. Therefore, transmission ofvibration to the outer housing 2 can be further effectively reduced.

Further, owing to the above-described arrangement of the elastic members13, the rotary shaft 78 can be stably held by the inner housing 3 (thecover 311) via the elastic members 13 before the rotary shaft 78 isassembled in the outer housing 2. Thereafter, both of the end portionsof the rotary shaft 78 are held between the upper shell 27 and the lowershell 28 of the outer housing 2, and the upper shell 27 and the lowershell 28 are connected together by screws, so that the rotary shaft 78is held by the outer housing 2. In this manner, the elastic members 13also help facilitate assembly. Further, the rotary shaft 78 is held in awell-balanced (evenly-balanced) manner by the two elastic members 13that are respectively disposed around the left and right end portions ofthe rotary shaft 78. Furthermore, the cylindrical elastic members 13 canbe easily assembled (mounted) by simply fitting them around the rotaryshaft 78.

As described above, the switch 29 for starting the motor 41 is held bythe rear part 23 of the outer housing 2 via the switch holder 20. Thus,a switching member (switch lever) 293 is connected to an actuation part291 of the switch 29 for switching ON and OFF the switch 29 and is alsoheld by the outer housing 2. The switching member 293 and structures forholding the switching member 293 are now described.

As shown in FIGS. 2 and 4 , the switching member (slide switch) 293 isan elongate member linearly extending in the front-rear direction. Theoperation part (tab, knob) 294 is integrally formed on a front endportion of the switching member 293. A rear end portion of the switchingmember 293 is operably connected to the actuation part (e.g., a lever orarm) 291 of the switch 29, which optionally may be a slide switch or atoggle switch. The switching member 293 is configured to move (slide,pivot) the actuation part 291 between an ON position and an OFF position(i.e. configured to switch ON and OFF the switch 29) by moving in thefront-rear direction in response to the user manually sliding theoperation part 294 in the front-rear direction. In this embodiment, theswitching member 293 is held by a holding member 26, which is supportedby the outer housing 2, so as to be movable (slidable) in the front-reardirection relative to the outer housing 2.

As shown in FIGS. 2, 4, 13 and 14 , the holding member 26 is supportedby the lower shell 28 and the switch holder 20 of the outer housing 2.The holding member 26 is configured to hold the switching member 293 soas to be slidable in the front-rear direction. In this embodiment, theholding member 26 includes a slide guide part 261 and support legs 263.

The slide guide part 261 has an elongate shape extending in thefront-rear direction and generally corresponding to the shape of theswitching member 293. The slide guide part 261 has a recess (groove)formed on its upper surface. The switching member 293 is disposed inthis recess so as to be slidable in the front-rear direction. Supportlegs 263 protrude from each of left and right edges of a front endportion of the slide guide part 261. As shown in FIG. 13 , each of thesupport legs 263 extends downward in a curved shape. Projections 283 areformed on each of left and right sides of a portion of the lower shell28 that forms a portion of the front part 21. The projections 283protrude upward from an upper end of the lower shell 28. The projections283 are formed in (at) positions that respectively correspond to thesupport legs 263, and receive (support) lower end portions of thesupport legs 263, respectively. Further, a rear end part 262 of theholding member 26 is mounted on and engaged with the switch holder 20,which is elastically connected to the rear part 38 of the inner housing3.

As shown in FIG. 14 , each of the support legs 263 has a recess (notch)having a semicircular shape in a plan view. A total of four cylindricalparts 285 is provided on the inside of the lower shell 28. The fourcylindrical parts 285 are disposed to respectively face (be disposed in)the recesses of the four support legs 263. An upper end of eachcylindrical part 285 is located below an upper end of the lower shell28. As shown in FIGS. 3 and 11 , a total of four cylindrical parts 271is provided on the upper shell 27. The four cylindrical parts 271 aredisposed in (at) positions that respectively correspond to the fourcylindrical parts 285. The cylindrical parts 271 protrude downward froma lower end of the upper shell 27. Each of the cylindrical parts 271 hasa female thread on its inner periphery. To assemble the oscillatingmulti-tool 1, the inner housing 3 and the holding member 26 are firsteach housed and supported in the lower shell 28, and then the uppershell 27 is connected to the lower shell 28. At this time, thecylindrical parts 271 of the upper shell 27 are fitted in the recessesof the support legs 263 and then in the cylindrical parts 285 of thelower shell 28. Thus, the holding member 26 can be properly (accurately)positioned relative to the outer housing 2. Thereafter, the lower shell28 and the upper shell 27 are fixed together by screws, which areinserted through the cylindrical parts 285 from below and threadedlyengage with the cylindrical parts 271.

Although not shown in detail, when the upper shell 27 is connected tothe lower shell 28, each of the support legs 263 extends along an innersurface of the upper shell 27 while being spaced apart from the innerhousing 3 within the outer housing 2. Further, as shown in FIG. 12 , theslide guide part 261 extends along a lower surface of an upper wall ofthe upper shell 27 while being spaced apart from the inner housing 3within the outer housing 2.

Further, as shown in FIGS. 13 and 14 , in this embodiment, the holdingmember 26 is configured to hold not only the switching member 293, butalso a light unit 260 for lighting a working area of the tool accessory91. For this purpose, the holding member 26 has a light-unit holdingpart 265 protruding forward from the slide guide part 261. Thelight-unit holding part 265 includes an extending part 266 and a pair ofarms 268. The extending part 266 linearly extends forward from a centerof a front end of the slide guide part 261 to forward of the rotaryshaft 78. The arms 268 extend downward, bifurcating from a front end ofthe extending part 266, and hold the light unit 260. The holding member26 is configured to guide a power supply wire 269 from the controller383 to the light unit 260. The wire 269 is held in a groove that isformed in an upper surface of the holding member 26 and extends from therear end part 262 to the light-unit holding part 265.

As shown in FIG. 8 , a groove 267 having a rectangular section is formedin a lower surface of the extending part 266 and extends in thefront-rear direction. The groove 267 is configured to be selectivelyfitted on (around) the large-diameter part of the eccentric part 781 ofthe rotary shaft 78. When the lever 77 is in the front position, thelarge-diameter part of the eccentric part 781 of the rotary shaft 78protrudes upward and is fitted in the groove 267. Thus, when the toolaccessory 91 is clamped, the light-unit holding part 265 is supported bythe rotary shaft 78 and held apart from the inner housing 3 within theouter housing 2. To assemble the oscillating multi-tool 1, an assembler(a person who assembles the oscillating multi-tool 1) can place the rearpart 38 and the light-unit holding part 265 on the switch holder 20 andthe rotary shaft 78, respectively, so that they are stably held beforemounting the inner housing 3 in the outer housing 2. This facilitatesthe mounting of the inner housing 3 and the holding member 26 in theouter housing 2.

The airflow paths within the housing 10 are now described.

As described above, in this embodiment, the housing 10 has a two-layeredstructure formed by the inner housing 3 and the outer housing 2.Therefore, air for cooling the motor 41 flows into the outer housing 2from the outside, and then into the inner housing 3. This air cools themotor 41 within the inner housing 3, flows out of the inner housing 3,and then flows out of the outer housing 2.

In this embodiment, as shown in FIGS. 2 and 3 , an opening is defined bya rear end (open end) of the rear part 23 of the outer housing 2 and theouter peripheral surface of the rear part 38 of the inner housing 3.This opening serves as an inlet 801 for drawing outside air into theouter housing 2. Further, as shown in FIGS. 2, 4 and 5 , inlets 803,804, 805 are formed in the inner housing 3 at different positions. Theinlets 803 are a plurality of through holes formed in right and leftwalls of the rear part 38 (specifically, the controller housing part382). The inlet 804 is the opening defined by the rear end of thecylindrical extending part 36. The inlets 805 are through holesrespectively formed in upper and lower walls of the extending part 36and extending linearly in the front-rear direction.

As shown in FIGS. 4 and 5 , outlets 807 are formed in the front part 30.The outlets 807 serve to discharge the air, which has cooled the motor41, from the inner housing 3. More specifically, the outlets 807 arethrough holes formed in a peripheral wall of the second housing part 32and are located radially outward of the fan 43. Further, as shown inFIG. 6 , outlets 809 are formed in a lower wall of the front part 21(more specifically, in a region below the motor 41). The outlets 809 arethrough holes that serve to discharge the air from the outer housing 2.Although not shown in detail, the outlets 809 are arranged side by sidein the left-right direction. Further, an opening is provided in thelower wall of the front part 21 such that the lower end portion of thespindle 5 is exposed to the outside through the opening, with a gaparound the spindle 5. Therefore, the air discharged from the innerhousing 3 can also flow out of the outer housing 2 through this gap.

Further, as shown in FIGS. 2, 3 and 5 , in this embodiment, a partition81 is provided between the outlets 807 and the inlets 803, 804, 805 ofthe inner housing 3. The partition 81 is configured to divide (partitionor separate) a space (gap or clearance) formed between the inner housing3 and the outer housing 2. Specifically, the partition 81 divides thespace formed between the inner housing 3 and the outer housing 2 into afront space in which the outlets 807 are disposed and a rear space inwhich the inlets 803, 804, 805 are disposed. The partition 81 has atapered tubular shape increasing in diameter toward the front. An endportion (i.e. a rear end portion) of the partition 81 having a smallerdiameter is connected to a front end portion of the extending part 36. Afront edge of the partition 81 is held in contact with the innerperiphery of the outer housing 2 and the slide guide part 261 of theholding member 26. In this embodiment, the partition 81 is formed of anelastically deformable elastomer. The partition 81 is integrally formedwith the plastic housing 302 (the left shell 303 and the right shell304).

The paths of airflow generated by rotation of the fan 43 and flowingwithin the housing are as follows. First, part of the air drawn into theouter housing 2 through the inlet 801 flows into the rear part 38through the inlets 803, cools the controller 383 and then flows forwardthrough a front end opening of the rear part 38. Another part of the airdrawn into the outer housing 2 from the inlet 801 flows forward throughthe gap between the rear part 23 and the rear part 38, and passes aroundthe elastic ribs 371 and the switch holder 20. Then, part of this airflows into the cylindrical extending part 36 through the inlet 804,while another part of this air passes through the gap between thecentral part 22 and the extending part 36 and flows into the extendingpart 36 through the inlets 805. In this embodiment, owing to the inlets804, 805 provided in the cylindrical extending part 36, the air flowsinto the extending part 36 and efficiently flows through the extendingpart 36 toward the front part 30.

The air led into the front part 30 mainly flows into the motor 41through a through hole formed in a central portion of the circuit boarddisposed on the top of the motor 41, and flows downward between thestator and the rotor and thereby cools the motor 41. The air is thendelivered (pushed) radially outward by the fan 43 and flows out of theinner housing 3 through the outlets 807 of the second housing part 32,and then flows out of the housing 10 through the outlets 809 of theouter housing 2.

The partition 81 is disposed between the outlets 807 and the inlets 803,804, 805, as described above. Therefore, the partition 81 can reduce thepossibility that the air that has been warmed while cooling the motor 41and that has flowed out through the outlets 807 will flow within theouter housing 2 and enter the inner housing 3 through the inlets 803,804, 805 again. Thus, the partition 81 serves to reduce the possibilityof a decrease of efficiency in cooling the motor 41.

Because the partition 81 is formed of elastomer and has a taperedtubular shape, the partition 81 will deform in response to a pressuredifference between the front space and the rear space, whereby aperipheral edge of the partition 81 will be pressed into close contactwith the inner periphery of the outer housing 2 and the slide guide part261. Therefore, the partition 81 can reliably block the air that hasflowed out through the outlets 807 from flowing into the rear space inwhich the inlets 803, 804, 805 are disposed. Further, the elasticallydeformable partition 81 can reduce the possibility that a gap will formbetween the partition 81 and the outer housing 2 when the inner housing3 and the outer housing 2 move relative to each other.

In some known oscillating multi-tools, the motor is arranged (oriented)such that the rotational axis of the output shaft (i.e. the rotationalaxis of the fan) intersects the driving axis of the spindle and extendsin parallel to the longitudinal axis of the inner housing. In this typeof known oscillating multi-tools, the air that flows in through theinlets and flows inside the inner housing in (along) the longitudinaldirection can pass the fan without changing the direction of flow, andwill then flow out via the outlets. With such an airflow path, the airthat has flowed out through the outlets does not easily flow toward theinlets.

In the oscillating multi-tool 1 of this embodiment, however, the motor41 is arranged (oriented) such that the rotational axis A2 of the outputshaft 415 (i.e. the rotation axis A2 of the fan 43) extends in parallelto the driving axis A1 of the spindle 5 and intersects the extensiondirection of the longitudinal axis of the inner housing 3. Owing to thisarrangement, the spindle 5 and the motor 41 can be arranged close toeach other, so that the oscillating multi-tool 1 can be made morecompact in the longitudinal direction. On the other hand, the directionof the airflow within the inner housing 3 must change in the vicinity ofthe motor 41. Specifically, the air that has flowed in through theinlets 803, 804, 805 flows forward within the extending part 36 alongthe longitudinal axis of the inner housing 3, changes the direction offlow in (at) an upper portion of the front part 30 (more specifically,in (at) the upper portion of the second housing part 32), and then flowsdownward within (through) the motor 41 and out via the outlets 807. Withsuch a structure, the air that has flowed out through the outlets 807can more easily flow toward the inlets 803, 804, 805, compared with theairflow paths in the above-described known type of oscillatingmulti-tools. Therefore, by providing the partition 81 in thisembodiment, an advantageous cooling effect can be achieved.

In this embodiment, because the inner housing 3 is formed by connectingthe metal housing 301 and the plastic housing 302, a gap may be formedat the connection (boundary) between the metal housing 301 and theplastic housing 302. Therefore, as a countermeasure, a closing member(blocking member, plugging member) 83 is provided in the oscillatingmulti-tool 1, as shown in FIG. 5 , to close any possible gap between themetal housing 301 and the plastic housing 302.

In this embodiment, a front end of the extending part 36 is in abutmentwith the second housing 32, but it is possible that a slight gap couldform therebetween. Therefore, the closing member 83 is configured toclose the gap between the second housing 32 and the extending part 36.The cover part 35 and an upper end portion of the second housing part 32are fixed into close contact with each other by screws. Further, theleft and right shells 303, 304 of the plastic housing 302 are also fixedinto close contact with each other by screws. Therefore, in thisembodiment, closing members for closing boundaries of these portions arenot provided. Similar closing members, however, may also be provided to(at) these portions.

In this embodiment, the closing member 83 is formed of elastomer, likethe partition 81. The closing member 83 is integrally formed with theplastic housing 302 (the left and right shells 303, 304) along the frontend of the extending part 36. When the metal housing 301 and the plastichousing 302 are connected together, the closing member 83 comes intoclose contact with the outer peripheral surface of the second housingpart 32 and closes the gap. Therefore, the closing member 83 can reducethe possibility that the air that has been warmed while cooling themotor 41 and that has flowed out through the outlets 807 will flow intothe inner housing 3 again through the gap between the second housingpart 32 and the extending part 36. Thus, the closing member 83 serves toreduce the possibility of a decrease of efficiency in cooling the motor41. If air were to (hypothetically) flow in through the gap between thesecond housing part 32 and the extending part 36, this air could beintroduced into the motor 41 from above by the fan 43. Therefore, it isadvantageous to close the gap between the second housing part 32 and theextending part 36.

In this embodiment, the partition 81 and the closing member 83 are bothintegrally formed with the inner housing 3 (the plastic housing 302) asdescribed above. This configuration makes assembly easier than in anembodiment in which the partition 81 and the closing member 83 areformed separately from the inner housing 3 and the outer housing 2.Further, the switching member 293 and the holding member 26 are heldwithin the outer housing 2. Therefore, assembly of the inner housing 3and the outer housing 2 is facilitated by providing the partition 81 onthe inner housing 3.

A modified embodiment is now described, with reference to FIGS. 15 and16 . In this modified embodiment, a lever 770 and a rotary shaft 780,which are respectively modified examples of the lever 77 and the rotaryshaft 78 (see FIG. 1 and FIG. 8 ), are described. It is noted thatstructures or components that are substantially identical to those ofthe above-described embodiment are given the same reference numerals asin the above-described embodiment, and may be omitted in the drawingsand the following description.

As shown in FIGS. 15 and 16 , like the lever 77 (see FIG. 1 ), the upperportion of the lever 770 is generally U-shaped; overall, the lever 770(and the lever 77) is Y-shaped. The lever 770 is a single member that isintegrally molded from synthetic resin/polymer. The lever 770 includes apair of arms 771 and a grip part (handle) 779.

The arms 771 each have a first end portion and a second end portion. Thefirst end portions of the arms 771 are engaged with an upper leftportion and an upper right portion of the front part 21 of the outerhousing 2, respectively. The first end portion of the arm 771 ishereinafter also referred to as an engagement portion 772. The left andright arms 771 extend along a left side surface and a right side surfaceof the front part 21 in a curved manner, and further extend such thatthe second end portions of the arms 771 are connected with each other ata center of the front part 21 in the left-right direction. The arms 771have flexibility and are elastically deformable (bendable) in adirection in which the distance therebetween changes (i.e. in theleft-right direction).

The engagement portion 772 of each arm 771 is engaged with the outerhousing 2 and includes a circular plate part 773, a cylindrical part 774and an inner flange 776. The circular plate part 773 is a circularplate-like portion that is disposed on an outer side (exterior) of theouter housing 2 (specifically, on the exterior of the left and rightside walls of the outer housing 2). The cylindrical part 774 is abottomed hollow circular cylindrical portion. The bottom of thecylindrical part 774 is closed by the circular plate part 773. Thecylindrical parts 774 of the of arms 771 protrude from the respectivecircular plate parts 773 toward each other. The cylindrical parts 774are held between the upper shell 27 and the lower shell 28, and extendalong the rotational axis A3 in the left-right direction. A plurality ofprojections 775 is formed inside each of the cylindrical parts 774. Theprojections 775 are arranged at equal intervals in the circumferentialdirection. The projections 775 each extend from an opening end of thecylindrical part 774 toward the circular plate part 773 in theleft-right direction. Each of the inner flanges 776 is an annularportion that protrudes radially outward from the end portion of thecylindrical part 774 that has the opening. The inner flanges 776 areeach disposed on an inner side (in the interior) of the outer housing 2(specifically, inside of the left and right side walls of the outerhousing 2).

The grip part 779 is a plate-like portion that protrudes from a portionwhere the arms 771 are connected with each other. The user can grasp thegrip part 779 to pivot the lever 770.

Like the rotary shaft 78 (see FIG. 8 ), the rotary shaft 780 extendsthrough the inner housing 3 in the left-right direction. The eccentricpart (cam part) 781 is provided on (at) a central portion of the rotaryshaft 780.

Left and right end portions of the rotary shaft 780 are connected to theengagement parts 772 of the left and right arms 771, respectively. Morespecifically, a plurality of engagement grooves 783 is formed in theouter periphery of both of the end portions of the rotary shaft 780. Theengagement grooves 783 are arranged at equal intervals in thecircumferential direction. The engagement grooves 783 each extend froman end of the rotary shaft 780 toward the center in the left-rightdirection. The engagement grooves 783 each have a shape that conforms tothe projection 775 of the engagement part 772. The end portions of therotary shaft 780 are fitted in the engagement parts 772 of the of arms771 in a state in which the engagement grooves 783 and the projections775 are engaged (meshed) with each other. Thus, the rotary shaft 780 issupported by the outer housing 2 via the lever 770, such that the rotaryshaft 780 is rotatable together with the lever 770.

An assembler can easily assemble the lever 770 and the rotary shaft 780to (in) the housing 10 in the following manner.

The assembler first inserts the rotary shaft 780 through the throughhole extending through the cover 311 in the left-right direction. Theassembler then fits the elastic members 13 around the left and right endportions of the rotary shaft 780. When the inside portions of theelastic members 13 are fitted in the recesses 313 of the cover 311,respectively, the rotary shaft 780 is stably held by the inner housing 3via the elastic members 13. The assembler can then elastically deformthe left and right arms 771 such that the engagement parts 772 arespaced farther away from each other to increase the distance betweenengagement parts 772. The assembler fits the engagement parts 772 on theleft and right end portions of the rotary shaft 780, such that theengagement grooves 783 and the projections 775 engage (mesh) with eachother. Owing to the elastic deformability of the polymer materialforming the lever 770, the arms 771 return to their initial positions inwhich the engagement parts 772 are closer to each other due to theelastic restoring force. The rotary shaft 780 and the lever 770 are thusconnected to each other so as to be rotatable together.

The left and right cylindrical parts 774 are then held (placed) betweenthe upper shell 27 and the lower shell 28 in the up-down direction and,in this state, the upper shell 27 and the lower shell 28 are connectedtogether by the screws. The lever 770 and the rotary shaft 780 are thussupported by the outer housing so as to be rotatable around therotational axis A3, and the assembly is completed.

When the assembly is completed, the circular plate part 773 and theinner flange 776 of the engagement part 772 are disposed on the outerside and on the inner side, respectively, of the outer housing 2, suchthat the side wall of the outer housing 2 is held between the circularplate part 773 and the inner flange 776. Owing to this arrangement,movement of the engagement part 772 in the left-right direction isblocked, and thereby elastic deformation of the arms 771 is restricted.In particular, the inner flanges 776, which are disposed on the innerside (in the interior) of the outer housing 2, block laterally outwardmovement of the engagement parts 772, and thereby effectively preventthe lever 770 from being disconnected from the rotary shaft 780.

Further, each inner flange 776 has an outside surface 777 that faces thecircular plate part 773 and an inside surface 778 that is on theopposite side from the the circular plate part 773. The outside surface777 and the inside surface 778 extend in parallel to each other and aredisposed opposite from each other in the left-right direction. Theoutside surface 777 and the inside surface 778 abut on the inner surfaceof the side wall of the outer housing 2 and on an end surface of thecircular cylindrical elastic member 13, respectively. With such anarrangement, the outer housing 2 and the elastic member 13 can beefficiently connected via the inner flanges 776, which also serve toprevent the lever 770 from being disconnected from the rotary shaft 780.

Correspondences between the features of the above-described embodimentsand the features of the present disclosure are as follows. The featuresof the above-described embodiments are merely exemplary and do not limitthe features of the present disclosure or the present invention.

The oscillating multi-tool 1 is an example of the “power tool”. Theinner housing 3 is an example of the “housing”. The spindle 5 and thetool mounting part 51 are examples of the “spindle” and the “toolmounting part”, respectively. The driving axis A1 is an example of the“driving axis”. The clamp shaft 61 is an example of the “clamp shaft”.The clamp spring 65 is an example of the “first biasing member”. Theclamp member 71 is an example of the “engagement member”. The collar 75is an example of the “first holding member”. The lever 77 is an exampleof the “manually operable member”. The push-down sleeve 671 is anexample of the “push-down member”. The inclined surface 513 and theinclined surface 913 are examples of the “first inclined surface” andthe “second inclined surface”, respectively. The holder 73 is an exampleof the “second holding member”. The groove 753 of the collar 75 is anexample of the “first recess”. The holding recess 733 of the holder 73is an example of the “second recess”. The biasing spring 675 is anexample of the “second biasing member”. The spring receiving member 57is an example of the “spring receiving part”. The elastic ring 718 is anexample of the “third biasing member”.

The above-described embodiments are merely exemplary embodiments of thepresent disclosure, and a power tool according to the present disclosureis not limited to the oscillating multi-tool 1 of the above-describedembodiment. For example, the following modifications may be made.Further, one or more of these modifications may be employed incombination with the oscillating multi-tool 1 of the above-describedembodiment or any one of the claimed features.

For example, the structure of the clamping mechanism 60 (for example,the shapes, arrangements and support structures of the clamp shaft 61and the clamp spring 65, and the components, shape, arrangement andsupport structure of the lock mechanism 7) may be appropriately changed.Examples of employable modifications are as follows.

For example, the clamp shaft 61 may be biased upward relative to thespindle 5, not via the holder 73 and the clamp member 71, but directlyby the clamp spring 65. Instead of the compression coil spring, theclamp spring 65 may be embodied, for example, as a tension coil spring,a torsion spring, a disc spring or a rubber spring.

In the above-described embodiment, the holder 73 has several functions(specifically, the functions of holding the clamp members 71, receivingthe biasing force of the clamp spring 65, and pushing down the push-downsleeve 671 in response to the unclamping operation of the lever 77). Theholder 73, however, need not have all of these functions. Thesefunctions may be performed by a plurality of different members(structures, components).

The clamp members 71 may be directly held by the collar 75. In such amodified embodiment, the holder 73 may be omitted. Furthermore, in sucha modified embodiment, for example, the clamp members 71 may be directlyor indirectly held by the inner housing 3 so as to be movable in theradial direction, and the collar 75 may be movable in the up-downdirection relative to the clamp members 71 and the spindle 5. In such amodified embodiment, the collar 75 may be configured to push down thepush-down sleeve 671 while the collar 75 moves downward. Further, thecollar 75 and the clamp members 71 may be configured such that the clampmembers 71 move relative to the collar 75 from the lock positions to theunlock positions when the collar 75 moves downward in response to theunclamping operation of the lever 77.

In the above-described embodiment, two of the clamp members 71 areprovided, but three or more clamp members 71 may be provided. Anengagement member that is configured to engage with the clamp shaft 61and hold the clamp shaft 61 in the clamp position is not limited to theabove-described clamp member(s) 71. For example, the (each) engagementmember may be embodied as a ball. In such a modified embodiment, inplace of the groove part 612, an annular groove may be formed in theupper end portion of the clamp shaft 61. The groove may have asemicircular cross-section, corresponding to the ball(s). One or more ofsuch balls may be provided. The structure of the collar 75 may also beappropriately changed, in accordance with such a change of the design ofthe clamp members 71. Further, the lock mechanism 7 may be disposedinside the spindle 5, for example, not above the spindle 5.

The shape, arrangement and support structure of the push-down sleeve 671or pusher may be appropriately changed, as long as the push-down sleeve671 is configured to be pushed down, e.g., by the holder 73 (or theclamp members 71) and/or the collar 75, and to push down the toolaccessory 91. For example, the shape of the large-diameter part 673 maybe appropriately changed. In order to more reliably eliminate stickingof the tool accessory 91 to the tool mounting part 51 (i.e. to detachthe tool accessory from the tool mounting part 51), however, it may bepreferable that the large-diameter part 673 comes into contact with thetool accessory 91 at multiple points (e.g., at 2 points that arediametrically (or at least substantially diametrically) opposite of eachother, or at least 3 points that define a plane) around the clamp shaft61, instead of at only one point. For example, the large-diameter part673 may come into contact with the tool accessory 91 in a regionsurrounding the clamp shaft 61 in the circumferential direction.Further, as was explained above, at least one rod-like or bar-likepush-down member may be provided, in place of the hollow cylindricalpush-down sleeve 671. Although the holder 73 abuts on and pushes downthe push-down sleeve 671 in the above-described embodiment, the holder73 may instead push down the push-down sleeve 671 via another member.Alternatively, the push-down sleeve 671 may be connected to the lowerend of the holder 73 so as to be movable in the up-down directiontogether with the holder 73.

Instead of the compression coil spring, the biasing spring 675 for thepush-down sleeve 671 may be embodied, for example, as a tension coilspring, a torsion spring, a disc spring or a rubber spring. Further, theposition of the biasing spring 675 is not limited to that of theabove-described embodiment.

The elastic ring 718 for temporarily holding the clamp shaft 61 when theclamp members 71 are located in the unlock positions may be an elasticelement other than rubber (for example, a metal elastic ring, such as agarter spring, more preferably an extension garter spring), or it may beomitted.

The shapes, arrangements and support structures of the lever 77, 770 andthe rotary shaft 78, 780 may be appropriately changed, as long as one ofthe clamp members 71 and the collar 75 (or its modification) is moveddownward in response to an external manual operation performed by theuser. For example, the lever 77, 770 may be modified to be rotatable(pivotable) around a pivot axis extending in the front-rear direction orin the up-down direction. The rotary shaft 78, 780 may be modified inaccordance with such a change of the lever 77, 770. Further, the rotaryshaft 78, 780 (the eccentric part 781) may push down the holder 73 notdirectly in abutment therewith but via another member.

The structure (for example, the shape and support structure) of thespindle 5 is not limited to that of the above-described embodiment, butmay be appropriately changed. For example, in the above-describedembodiment, the tool mounting part 51 has the recess 351 thatcorresponds to the protruding part 911 of the tool accessory 91, so thatthe tool accessory 91 is secured (fixed, attached) to the tool mountingpart 51 in a state in which the inclined surface 913 is in abutment withthe inclined surface 513 of the tool mounting part 51. However, the toolmounting part 51 may have a planar lower surface, to (on) which a toolaccessory having a planar upper surface is secured (fixed, attached). Insuch an embodiment, in order to position the tool accessory relative tothe tool mounting part 51, the tool mounting part 51 and the toolaccessory may have projections and fitting holes, respectively. In sucha modified embodiment, like the inclined surfaces 513, 913, theprojections and the fitting holes may have respective inclined surfacesthat are inclined (oblique) relative to the driving axis A1 and conform(are complementary) to each other.

The structures (for example, the shapes, structures (elements) housedtherein and arrangements) of the housing 10, the motor 41 and thetransmitting mechanism 45 may be appropriately changed. For example, theelastic members 11, 13, 15 disposed between the inner housing 3 and theouter housing 2 may be formed of a material that is different from thematerial of the above-described embodiment. For example, rubber or afoam of a different kind of synthetic resin/polymer can be employed. Theshapes, numbers and positions of the elastic members 11, 13, may bedifferent from those of the above-described embodiment. The housing 10need not be a vibration-isolating housing that includes the outerhousing 2 elastically connected to the inner housing 3. In other words,a housing having a single-layer structure may be employed. Components ofthe outer housing 2 and the inner housing 3 and the manner of connectingthe outer housing 2 and the inner housing 3 may also be appropriatelychanged. The airflow paths within the housing 10 may be different fromthose of the above-described embodiment. Further, for example, the motor41 may be an AC motor. In some aspects of the present teachings, themotor 41 may be housed within the grip part (the central part 22) of thehousing 10 such that the rotational axis A2 of the output shaft 415 isorthogonal or oblique to the driving axis A1.

Further, in view of the nature of the present disclosure, theabove-described embodiment and the modifications thereof, the followingAspects 1 to 5 can be provided. Any one of the following Aspects 1 to 5can be employed alone or in combination with any one of the oscillatingmulti-tools 1 of the above-described embodiment, the above-describedmodifications and the claimed features.

(Aspect 1)

The manually operable member (lever) is configured to move theengagement member(s) downward relative to the first holding member inresponse to the unclamping operation, and

the second position of the engagement member(s) is located below thefirst position.

(Aspect 2)

The push-down sleeve is inserted through the spindle, and

the second holding member is configured to abut on an upper end of thepush-down sleeve and push down the sleeve above the spindle when thesecond holding member moves downward.

(Aspect 3)

A first one of the clamp shaft and the engagement member(s) has arecess, and a second (other) one of the clamp shaft and the engagementmember(s) has a projection configured to engage (mesh) with the recesswhen the engagement member(s) is (are) placed in the first position.

The groove part 612 and the ridge part 717 are examples of the “recess”and the “projection”, respectively, in this Aspect.

(Aspect 4)

A multi-tool comprising:

a spindle configured to be pivoted in an oscillating manner around adriving axis that is parallel to an up-down direction of the multi-tool;

a tool mounting surface defined at a lower end of the spindle;

a clamping shaft disposed coaxially with the spindle and configured tobe movable relative to, and removable from, the spindle;

a clamping head defined at a lower end of the clamping shaft;

a first biasing member configured to bias the clamping shaft upward inthe up-down direction toward a clamping position at which a toolaccessory is clampable between the clamping head and the tool mountingsurface;

a manually operable lever; and

a pusher extending in parallel to the spindle;

wherein:

in response to pivoting of the manually operable lever toward anunclamping position, the pusher is configured to move downward in theup-down direction relative to the spindle to push the tool accessoryaway from the tool mounting surface of the spindle.

(Aspect 5)

The multi-tool according to Aspect 4, wherein:

the tool mounting surface comprises a first inclined and/or curvedsurface that extends obliquely to or in a non-parallel manner with thedriving axis, andthe tool accessory has a second inclined and/or surface that iscomplementary to the first inclined and/or curved surface and mates withthe first inclined and/or curved surface at least multiple contactpoints disposed around the driving axis when the tool accessory isclamped between the clamping head and the tool mounting surface of thespindle.

The following Aspects 6 to 23 are described with the aim of providingtechniques for avoiding or minimizing a decrease of efficiency incooling a motor of a power tool having an inner housing and an outerhousing. Each one of the following Aspects 6 to 23 may be employedindividually or in combination with any one or more of the otheraspects. Alternatively, at least one of the following Aspects 6 to 23may be employed in combination with at least one of the oscillatingmulti-tools 1 of the above-described embodiment, the above-describedmodifications and aspects, and the claimed features.

(Aspect 6)

A power tool configured to drive a tool accessory in an oscillatingmanner, the power tool comprising:

a motor;

a spindle that is supported to be rotatable around a driving axis andconfigured to pivotally oscillate the tool accessory that is removablymounted to (on) the spindle using power (motive power) generated by themotor;

an inner housing that houses the motor and the spindle and that has atleast one inlet (port, opening) and at least one outlet (port, opening);

an outer housing that houses (surrounds) the inner housing and that iselastically connected to the inner housing to be movable relative to theinner housing; and

a partition that is disposed between the at least one inlet and the atleast one outlet, the partition dividing a space (clearance, emptyspace, airflow path) formed between the inner housing and the outerhousing.

In the power tool of this Aspect, at least one space (gap, clearance) isformed between the inner housing and the outer housing that areelastically connected to be movable relative to each other. Air flowsinto the inner housing through the at least one inlet, cools the motor,and then flows out into this space through the at least one outlet. Thepartition is provided in this space between the at least one outlet andthe at least one inlet, so that the space is divided into a first space(inlet-side space) in which the at least one inlet is disposed and asecond space (outlet-side space) in which the at least one outlet isdisposed. The partition can reduce the amount of the air, which hasflowed out through the at least one outlet into the second space(outlet-side space), that flows into the first space (inlet-side space)again. This can reduce the possibility that the air that has been warmedwhile cooling the motor will flow into the inner housing again throughthe at least one inlet, thereby avoiding a decrease of efficiency incooling the motor.

(Aspect 7)

The power tool as defined in Aspect 6, wherein the partition is providedon (attached to) the inner housing.

According to this aspect, an assembler can easily assemble the innerhousing and the outer housing even if there is a component to beassembled (placed) into the outer housing.

(Aspect 8)

The power tool as defined in Aspect 7, wherein the partition isintegrally formed with the inner housing.

According to this aspect, the assembly can be further facilitated.

(Aspect 9)

The power tool as defined in any one of Aspects 6 to 8, wherein thepartition is formed of an elastic element configured to deform underpressure, e.g., in response to changes in air pressure between the twospaces divided by the elastic element.

According to this aspect, the partition can deform in response to an airpressure difference between the first space (inlet-side space) and thesecond space (outlet-side space) across the partition, and thereby comeinto closer contact with the inner housing and the outer housing. Thiscan further reduce the amount of the air that flows into the first space(inlet-side space) again.

(Aspect 10)

The power tool as defined in any one of Aspects 6 to 9, wherein:

the inner housing is formed by connecting a plurality of members,

the power tool further comprises a closing member that at least partlycloses a gap between the plurality of members.

According to this aspect, the possibility can be reduced that the airthat has been warmed while cooling the motor will flow into the innerhousing again through the gap between the plurality of members that formthe inner housing.

(Aspect 11)

The power tool as defined in Aspect 10, wherein both of the partitionand the closing member are integrally formed with either the innerhousing or the outer housing.

(Aspect 12)

The power tool as defined in Aspect 11, wherein both of the partitionand the closing member are integrally formed with the inner housing.

According to Aspects 9 and 10, the assembly is further facilitated.

(Aspect 13)

The power tool as defined in any one of Aspects 6 to 12,

wherein the inner housing includes:

-   -   a first end part that houses at least the spindle; and    -   a cylindrical part that extends in a longitudinal direction of        the outer housing and that has an open end and a connecting end        connected to the first end part,

wherein the at least one outlet is formed in the first end part, and

wherein the at least one inlet includes at least one of a first openingof the open end of the cylindrical part and a second opening formed in aperipheral wall that defines the cylindrical part.

According to this aspect, an efficient path can be defined along whichthe air flows in the longitudinal direction within the elongatecylindrical part toward the first end part.

(Aspect 14)

The power tool as defined in any one of Aspects 6 to 13, wherein:

the motor has an output shaft, and

the spindle and the motor are arranged such that the driving axis and arotational axis of the output shaft extend in parallel to each other.

According to this aspect, the spindle and the motor can be arrangedrelatively close to each other, so that a power tool that is morecompact in the longitudinal direction can be obtained.

(Aspect 15)

The power tool further comprises a fan that is configured to rotatetogether with the output shaft.

(Aspect 16)

The partition is disposed closer to the at least one outlet than to theat least one inlet.

(Aspect 17)

The outer housing has at least one inlet and at least one outlet, and

the partition divides the space between the at least one inlet of theouter housing and the at least one outlet of the outer housing.

(Aspect 18)

The partition divides the space formed between the inner housing and theouter housing into an inlet-side space in which the at least one inletis located and an outlet-side space in which the at least one outlet islocated, and

the closing member is provided on (at) a portion of the inner housinglocated in the outlet-side space.

(Aspect 19)

The power tool further comprises a fan that is configured to rotatetogether with the output shaft,

the inner housing includes a motor housing part that houses the motorand the fan, and

the closing member is configured to close a gap between the motorhousing part and a member that is connected to the motor housing part.

(Aspect 20)

The closing member is formed of an elastic element, e.g., made of anelastomer.

(Aspect 21)

The inner housing is an elongate member having a longitudinal axis thatintersects the driving axis,

the inner housing includes a first end part that houses at least thespindle, a second end part located opposite to the first end part, and aconnecting part extending in a direction of the longitudinal axis andconnecting the first end part and the second end part,

the partition is provided on the connecting part,

the at least one outlet is provided in the first end part, and

the at least one inlet is provided in at least one of the second partand the connecting part.

(Aspect 22)

The first end part houses the motor.

(Aspect 23)

The connecting part includes:

-   -   a cylindrical part having an open end and a connecting end that        is connected to the first end part, the cylindrical part        extending toward the second end part; and    -   a plurality of connecting members connecting the open end of the        cylindrical part and the second end part, and

wherein the at least one inlet includes at least one of a first openingformed in the second end part, a second opening of the open end of thecylindrical part and a third opening formed in a peripheral wall thatdefines the cylindrical part.

Correspondences between the features of the above-described embodimentand the features of the Aspects 6 to 23 are as follows. The features ofthe above-described embodiment are merely exemplary and do not limit thefeatures of the present disclosure or the present invention.

The oscillating multi-tool 1 is an example of the “power tool”. Themotor 41 is an example of the “motor”. The spindle 5 is an example ofthe “spindle”. The driving axis A1 is an example of the “driving axis”.The inner housing 3 is an example of the “inner housing”. Each of theinlets 803, 804, 805 is an example of the “inlet of the inner housing”.The outlet 807 is an example of the “outlet of the inner housing”. Theouter housing 2 is an example of the “outer housing”. The partition 81is an example of the “partition”. The metal housing 301 and the plastichousing 302 are an example of the “plurality of members”. The closingmember 83 is an example of the “closing member”. The front part 30 ofthe inner housing 3 is an example of the “first end part”. The extendingpart 36 is an example of the “cylindrical part”. The output shaft 415 isan example of the “output shaft”. The rotational axis A2 is an exampleof the “rotational axis of the output shaft”. The fan 43 is an exampleof the “fan”. The inlet 801 and the outlet 809 are examples of the“inlet of the outer housing” and the “outlet of the outer housing”. Thesecond housing part 32 is an example of the “motor housing part”. Therear part 38 is an example of the “second end part”. The elastic ribs371 are an example of the “plurality of connecting members”.

The power tool as defined in Aspects 6 to 23 is not limited to theoscillating multi-tool 1 of the above-described embodiment. For example,the following modifications may be made. At least one of thesemodifications may be adopted in combination with at least one of theoscillating multi-tools 1 of the above-described embodiment, theabove-described modifications and aspects, and the claimed features.

For example, the structures (for example, the shapes, components andconnecting manner) of the housing 10 (the inner housing 2 and the outerhousing 3) may be appropriately changed. For example, each of the metalhousing 301 and the plastic housing 302 of the inner housing 3 may havea different shape. The plastic housing 302 may be formed by connectingan upper shell and a lower shell. The outer housing 2 may be formed byconnecting a left shell and a right shell. The inner housing 3 mayinclude only the front part 30 (the metal housing 301) that houses thespindle 5, etc. Further, the front part 30 and the rear part 38 may beconnected only via the extending part 36. A single elastic elementhaving a lower elastic modulus than the extending part 36 may beemployed, in place of the elastic ribs 371.

The airflow paths within the housing 10 may be different from those ofthe above-described embodiment. Specifically, the shapes, numbers,positions etc., of the inlets 801, 803, 804, 805 and the outlets 807,809 may be appropriately changed, in accordance with or regardless of achange in the housing 10 and the structures (elements) disposed therein.

For example, the inlet 801 may be a through hole (port) formed in therear part 23. In an embodiment in which the controller 383 is disposedin the extending part 36, the inlets 803 may be omitted. The inlet(s)805 may be formed in only one of the upper wall and the lower wall ofthe extending part 36, or may be omitted. Because the fan 43 is acentrifugal fan, it is preferable that the outlets 807 are locatedradially outward of the fan 43. The outlets 807, however, may bedisposed in (at) other positions. In a modified embodiment in which anaxial fan is employed, for example, the outlets 807 may be formed in thelower wall of the second housing part 32.

The material, shape, position of the partition 81 may be appropriatelychanged. For example, the partition 81 may be formed of a different kindof elastic element (e.g. a synthetic resin/polymer foam), in place ofelastomer. The partition 81 may be shaped in a simple annular form,rather than a tapered cylindrical form. The partition 81 may beintegrally formed with the outer housing 2, or may be a member that isformed separately from the inner housing 3 and the outer housing 2.Further, the partition 81 may be disposed in (at) any position betweenthe inlets 803, 804, 805 and the outlets 807. However, it may bepreferable that the partition 81 is disposed as close as possible to theoutlets 807. Although the partition 81 need not completely isolate (i.e.completely prohibit communication of the air between) the rear space, inwhich the inlets 803, 804, 805 are located, and the front space, inwhich the outlets 807 are located, it may be preferable that gapsbetween the partition 81 and inner housing 3 and between the partition81 and the outer housing 2 are made as small as possible.

The material, shape, position of the closing member 83 may beappropriately changed. For example, the closing member 83 may be formedof a different kind of elastic element (e.g. a synthetic resin/polymerfoam), in place of elastomer. The closing member 83 may be formed as aseparate member from the inner housing 3, and may be disposed to coverthe gap or fitted in the gap.

The structure of the clamping mechanism 60 (for example, the shapes,arrangements and support structures of the clamp shaft 61 and the clampspring 65, and the components, shape, arrangement and support structureof the lock mechanism 7) may be appropriately changed. For example, amechanism may be employed that is configured to hold the clamp shaft 61in the clamp position using at least one ball, in place of the clampmembers 71. The lever 77, 770 and the rotary shaft 78, 780 may bechanged in accordance with the change in the clamp mechanism 60.Further, the clamp mechanism 60 may be omitted, and the clamp shaft 61may be secured to the spindle 5 using a screw.

The structure of the push-down mechanism 67 (the shape, arrangement andsupport structure of the push-down sleeve 671, and a type of the biasingspring 675, for example) may be appropriately changed. Further, thepush-down mechanism 67 may be omitted in some aspects of the presentteachings.

The structures (the shape, support structure, etc.) of the spindle 5,the motor 41 and the transmitting mechanism 45 may be appropriatelychanged. For example, in the above-described embodiment, the toolmounting part 51 has the recess 351 that corresponds to the protrudingpart 911 of the tool accessory 91, so that the tool accessory 91 issecured to the tool mounting part 51 in a state in which the inclinedsurface 913 is in abutment with the inclined surface 513 of the toolmounting part 51. However, the tool mounting part 51 may have a planarlower surface, to (on) which a tool accessory having a planar uppersurface is secured. Further, the motor 41 may be an AC motor powered bya commercial AC power source via a power cord, instead of by thebattery. The motor 41 may be housed within the grip part (the centralpart 22) of the housing 10 such that the rotational axis A2 of theoutput shaft 415 is orthogonal to the driving axis A1. Moreover,although the transmitting mechanism 45 of the above-described embodimentincludes an eccentric shaft 451, a drive (ball) bearing 456, and anoscillating arm (fork) 458, the mechanism for converting the rotationaloutput of the output shaft 415 into pivotal oscillating motion of thespindle 5 is not particularly limited and may be modified withoutdeparting from the scope of the present teachings. For example, thedrive bearing 456 need not be a ball bearing and may be another type ofbearing, such as, e.g., a needle bearing or spherical bearing. Theoscillating arm 458 need not be bifurcated; it may have a single arm oran annular portion that encircles the drive bearing 456.

The following Aspects 24 to 39 are described with the aim of providingrational arrangements of at least one elastic member in a power toolhaving an inner housing and an outer housing. Each one of the followingAspects 24 to 39 may be employed individually or in combination with anyone or more of the other aspects. Alternatively, at least one of thefollowing Aspects 24 to 39 may be employed in combination with at leastone of the oscillating multi-tools 1 of the above-described embodiment,the above-described modifications and aspects, and the claimed features.

(Aspect 24)

A power tool configured to drive a tool accessory in an oscillatingmanner (in a pivotal oscillating manner), the power tool comprising:

a spindle supported to be rotatable around a first axis and configuredto pivotally oscillate the tool accessory that is removably mounted to alower end portion of the spindle in an oscillation plane, the first axisdefining or being in parallel to an up-down direction of the power tool;

a motor having an output shaft configured to rotate around a secondaxis, the second axis extending parallel to the first axis;

an oscillating arm connected to the spindle and configured to oscillateabout the first axis in response to rotation of the output shaft andthereby drive the spindle with a rotary (pivotal) oscillating motionaround the first axis;

an inner housing that houses the spindle, the motor and the oscillatingmember;

an outer housing that houses the inner housing, the outer housing beingan elongate hollow body having a longitudinal axis, the longitudinalaxis being orthogonal to the first and second axes and defining afront-rear direction of the power tool; and

at least one first elastic member disposed between the inner housing andthe outer housing,

wherein the at least one first elastic member is located between theoscillation plane and an upper end of the oscillating member in theup-down direction and between the first axis and the second axis in thefront-rear direction.

In the power tool of this Aspect, the output shaft of the motor and thespindle generate vibration when they are rotationally driven. To copewith this vibration, the at least one first elastic member, which isdisposed between the inner housing and the outer housing, is locatedbetween the first axis of the spindle and the second axis of the outputshaft in the front-rear direction, thereby effectively reducingtransmission of vibration to the outer housing. Further, the at leastone first elastic member is located between the oscillation plane andthe upper end of the oscillating member in the up-down direction andthus in (at) a position relatively close to the oscillation plane. Thisarrangement can reduce wobbling (rattling) of the inner housing withinthe outer housing during oscillatory driving of the tool accessory.Thus, according to this Aspect, the at least one first elastic member isrationally arranged.

(Aspect 25)

The power tool as defined in Aspect 24, wherein the at least one firstelastic member is disposed under the inner housing.

According to this aspect, the at least one first elastic member can belocated in (at) a position closer to the oscillation plane.

(Aspect 26)

The power tool as defined in Aspects 24 or 25, wherein:

the at least one first elastic member has a cylindrical shape having anouter peripheral surface and an inner peripheral surface,

a first one of the inner housing and the outer housing is in abutmentwith the outer peripheral surface of the at least one first elasticmember, and

a second one of the inner housing and the outer housing is in abutmentwith the inner peripheral surface of the at least one first elasticmember.

According to this aspect, the inner housing and the outer housing can beelastically connected to be movable in multiple directions relative toeach other by the first elastic member that has a simple structure.

(Aspect 27)

The power tool as defined in any one of Aspects 24 to 26, wherein:

a direction that is orthogonal to the up-down direction and thefront-rear direction is defined as a left-right direction of the powertool, and

the at least one first elastic member includes a plurality of firstelastic members arranged side by side in the left-right direction.

According to this Aspect, a more durable elastically connectingstructure can be provided than in an embodiment in which a single firstelastic member is employed.

(Aspect 28)

The power tool as defined in any one of Aspects 24 to 27, wherein:

a direction that is orthogonal to the up-down direction and thefront-rear direction is defined as a left-right direction of the powertool, and

the at least one first elastic member is configured to allow the innerhousing and the outer housing to move relative to each other in theup-down direction, the front-rear direction and a left-right direction.

According to this aspect, the power tool is capable of coping withvibrations in at least three directions that are orthogonal to eachother.

(Aspect 29)

The power tool as defined in any one of Aspects 24 to 28, furthercomprising:

a clamp shaft that is disposed to be coaxial with the spindle andconfigured to clamp the tool accessory in cooperation with the lower endportion of the spindle;

a manually operable member (lever) for unclamping the tool accessory,the manually operable member having a support shaft that is rotatablysupported by the outer housing; and

at least one second elastic member disposed between the inner housingand the support shaft,

wherein the at least one second elastic member is disposed around thesupport shaft.

According to this Aspect, transmission of vibration to the outer housingcan be effectively reduced not only by the at least one first elasticmember but also by the at least one second elastic member.

(Aspect 30)

The power tool as defined in Aspect 29, wherein:

a direction that is orthogonal to the up-down direction and thefront-rear direction is defined as a left-right direction of the powertool,

the at least one second elastic member includes a plurality of secondelastic members arranged on left and right sides of the first axis inthe left-right direction, and

each of the second elastic members has a hollow cylindrical (annular)shape and is fitted around the support shaft.

According to this aspect, the support shaft can be held in awell-balanced (evenly-balanced) manner with an easy-to-assemblestructure.

(Aspect 31)

The power tool as defined in Aspect 29 or 30, wherein:

the at least one second elastic member is configured such that the innerhousing and the support shaft are movable relative to each other in theup-down direction, the front-rear direction and the left-rightdirection.

According to this Aspect, vibration-isolating performance can be furtherimproved.

(Aspect 32)

The power tool as defined in any one of Aspects 29 to 31, wherein:

the manually operable member has two arms respectively connected toaxial end portions of the support shaft, and

the two arms each have an engagement part that is directly fitted ontothe respective axial end portions of the support shaft.

According to this aspect, the manually operable member can be easilyassembled, without increasing the number of components (part count).

(Aspect 33)

The power tool as defined in Aspect 32, wherein:

the two arms are connected to each other at a single member and areconfigured to elastically deform such that the distance between the twoarms is changeable, and

elastic deformation of the two arms is restricted by the engagementparts of the two arms being engaged with the outer housing.

According to this Aspect, an assembler can easily engage the engagementparts with the axial end portions of the support shaft by elasticallydeforming the arms in a direction away from each other. Furthermore,engagement between the engagement parts and the outer housing can reducethe possibility that the arms will subsequently disconnect from thesupport shaft.

(Aspect 34)

The power tool as defined in Aspect 33, wherein:

each of the engagement parts includes an abutment part, each of theabutment parts is arranged radially outward of the support shaft and onthe inner side (in the interior) of the outer housing,

each of the abutment parts has a first abutment surface that abuts onthe outer housing and a second abutment surface that abuts on the atleast one second elastic member, and

the first abutment surface and the second abutment surface are disposedopposite from each other in an axial direction of the support shaft.

According to this Aspect, the outer housing and the at least one secondelastic member can be efficiently connected via the abutment part.

(Aspect 35)

The outer housing includes a grip part configured to be held by a user.

(Aspect 36)

The spindle, the motor and the oscillating arm are housed in a frontpart of the outer housing.

(Aspect 37)

The inner housing extends in the front-rear direction, and

the spindle, the motor and the oscillating arm are housed in a frontpart of the inner housing.

(Aspect 38)

The front part of the inner housing includes:

-   -   a first housing part that houses the spindle;    -   a second housing part that houses the motor; and    -   a third housing part that is located rearward of the first        housing part and below the second housing part and that houses        the oscillating arm,

wherein the at least one first elastic member is disposed between thethird housing part and the outer housing.

(Aspect 39)

The power tool further comprises at least one third elastic memberdisposed between a rear part of the inner housing and the outer housing.

Correspondences between the features of the above-described embodimentand the features of the Aspects 24 to 39 are as follows. The features ofthe above-described embodiment are merely exemplary and do not limit thefeatures of the present invention.

The oscillating multi-tool 1 is an example of the “power tool”. Thespindle 5 is an example of the “spindle”. The driving axis A1 is anexample of the “first axis”. The tool mounting part 51 is an example ofthe “lower end portion of the spindle”. The oscillation plane P is anexample of the “oscillation plane”. The motor 41 and the output shaft415 are examples of the “motor” and the “output shaft”, respectively.The rotational axis A2 is an example of the “second axis”. Theoscillating arm 458 is an example of the “oscillating member”. The innerhousing 3 is an example of the “inner housing”. The outer housing 2 isan example of the “outer housing”. The elastic member 11 is an exampleof the “first elastic member”. The clamp shaft 61 is an example of the“clamp shaft”. The lever 77 and the rotary shaft 78 as a whole is anexample of the “manually operable member”. The lever 770 and the rotaryshaft 780 as a whole is another example of the “manually operablemember”. Each of the rotary shafts 78, 780 is an example of the “supportshaft”. The elastic member 13 is an example of the “second elasticmember”. The pair of arms 771 is an example of the “pair of arms”. Theengagement part 772 is an example of the “engagement part”. The innerflange 776 is an example of the “abutment part”. The outside surface 777and the insider surface 778 are examples of the “first abutment surface”and the “second abutment surface”, respectively. The central part 22 isan example of the “grip part”. The first housing part 31, the secondhousing part 32, and the third housing part 33 are examples of the“first housing part”, “second housing part” and “third housing part”,respectively. The elastic member 15 is an example of the “third elasticmember”.

The power tool as defined in Aspects 24 to 39 is not limited to theoscillating multi-tools 1 of the above-described embodiment, themodified embodiments or the claimed features. For example, the followingmodifications may be made. At least one of these modifications may beadopted in combination with at least one of the oscillating multi-tool 1of the above-described embodiment, the above-described modifications andaspects, and the claimed features.

For example, the material, shapes, numbers, positions etc. of theelastic members 11, 13, disposed between the inner housing 3 and theouter housing 2 may be appropriately modified. Examples of employablemodifications are as follows.

For example, each of the elastic members 11, 13, 15 may be formed of amaterial that is different from the material of the above-describedembodiment. For example, rubber or a foam of a different kind ofsynthetic resin/polymer can be employed.

Further, only one elastic member 11 may be employed, or three or moreelastic members 11 may be employed. The position(s) of the elasticmember(s) 11 may be changed, as long as the position(s) is (are) betweenthe oscillation plane P and the upper end of the oscillating arm 458 inthe up-down direction, and also between the driving axis A1 and therotation axis A2 in the front-rear direction. For example, a leftelastic member 11 may be disposed over a left side surface and the lowersurface of the third housing part 33, between the third housing part 33and the front part 21. Correspondingly, a right elastic member 11 may bedisposed over a right side surface and the lower surface of the thirdhousing part 33, between the third housing part 33 and the front part21. In such an embodiment, it may be preferable that each of the leftand right elastic members 11 is disposed to form an L shape as viewedfrom the front or from the rear, so that the left and right elasticmembers 11 can efficiently cope with the vibrations in the left-rightdirection and the up-down direction.

The components and connecting manner of the inner housing 2 and theouter housing 3 may be appropriately changed. For example, each of themetal housing 301 and the plastic housing 302 of the inner housing 3 mayhave a different shape. The plastic housing 302 may be formed byconnecting an upper shell and a lower shell. The outer housing 2 may beformed by connecting a left shell and a right shell. The airflow pathswithin the housing 10 may be different from those of the above-describedembodiment. The inner housing 3 may have only the front part (the metalhousing 301) that houses the spindle 5, etc. Further, the front part 30and the rear part 38 may be connected only via the extending part 36. Asingle elastic element having a lower elastic modulus than the extendingpart 36 may be employed, in place of the elastic ribs 371.

The structure of the clamping mechanism 60 (for example, the shapes,arrangements and support structures of the clamp shaft 61 and the clampspring 65, and the components, shape, arrangement and support structureof the lock mechanism 7) may be appropriately changed. For example, amechanism may be employed that is configured to hold the clamp shaft 61in the clamp position using at least one ball, in place of the clampmembers 71. The lever 77, 770 and the rotary shaft 78, 780 may bechanged in accordance with the change in the clamp mechanism 60.Further, the clamp mechanism 60 may be omitted, and the clamp shaft 61may be secured to the spindle 5 using a screw.

The structure of the push-down mechanism 67 (the shape, arrangement andsupport structure of the push-down sleeve 671, and a type of the biasingspring 675, for example) may be appropriately changed. Further, thepush-down mechanism 67 may be omitted in some aspects of the presentteachings.

The structures (the shape, support structure, etc.) of the spindle 5,the motor 41 and the transmitting mechanism 45 may be appropriatelychanged. For example, in the above-described embodiment, the toolmounting part 51 has the recess 351 that corresponds to the protrudingpart 911 of the tool accessory 91, so that the tool accessory 91 issecured to the tool mounting part 51 in a state in which the inclinedsurface 913 is in abutment with the inclined surface 513 of the toolmounting part 51. However, the tool mounting part 51 may have a planarlower surface, to which a tool accessory having a planar upper surfaceis secured. In the alternative, the tool mounting part 51 may define arecess having a rounded star-shaped configuration, into which a toolaccessory having protrusion with a complementary (corresponding) roundedstar-shaped configuration is insertable so that the rounded star-shapedstructures interlock with each other in a form-fit (shape-fit) manner.Further, the motor 41 may be an AC motor. The motor 41 may be housedwithin the grip part (the central part 22) of the housing 10 such thatthe rotational axis A2 of the output shaft 415 is orthogonal to thedriving axis A1.

Representative, non-limiting examples of the present invention weredescribed above in detail with reference to the attached drawings. Thisdetailed description is merely intended to teach a person of skill inthe art further details for practicing preferred aspects of the presentteachings and is not intended to limit the scope of the invention.Furthermore, each of the additional features and teachings disclosedabove may be utilized separately or in conjunction with other featuresand teachings to provide improved power tools that drive a toolaccessory with an oscillating motion.

Moreover, combinations of features and steps disclosed in the abovedetailed description may not be necessary to practice the invention inthe broadest sense, and are instead taught merely to particularlydescribe representative examples of the invention. Furthermore, variousfeatures of the above-described representative examples, as well as thevarious independent and dependent claims below, may be combined in waysthat are not specifically and explicitly enumerated in order to provideadditional useful embodiments of the present teachings.

All features disclosed in the description and/or the claims are intendedto be disclosed separately and independently from each other for thepurpose of original written disclosure, as well as for the purpose ofrestricting the claimed subject matter, independent of the compositionsof the features in the embodiments and/or the claims. In addition, allvalue ranges or indications of groups of entities are intended todisclose every possible intermediate value or intermediate entity forthe purpose of original written disclosure, as well as for the purposeof restricting the claimed subject matter.

DESCRIPTION OF THE REFERENCE NUMERALS

-   -   1: oscillating multi-tool, 10: housing, 11: elastic member, 13:        elastic member, 15: elastic member, 2: outer housing, 20: switch        holder, 203: recess, 21: front part, 215: projection, 22:        central part (grip part), 23: rear part, 26: holding member,        260: light unit, 261: slide guide part, 262: rear end part, 263:        support leg, 265: light-unit holding part, 266: extending part,        267: groove, 268: arm, 269: wire, 27: upper shell, 271:        cylindrical part, 28: lower shell, 283: projection, 285:        cylindrical part, 29: switch, 291: actuation part, 293:        switching member, 294: operation part, 3: inner housing, 30:        front part, 301: metal housing, 302: plastic housing, 303: left        shell, 304: right shell, 31: first housing part, 311: cover,        313: recess, 32: second housing part, 321: connecting part, 33:        third housing part, 335: recess, 35: cover part, 351: recess,        36: extending part, 37: elastic connection part, 371: elastic        rib, 38: rear part, 381: battery mounting part, 382: controller        housing part, 383: controller, 385: arm part, 386: projection,        41: motor, 415: output shaft, 43: fan, 45: transmitting        mechanism, 451: eccentric shaft, 452: bearing, 453: bearing,        454: eccentric part, 456: drive bearing, 458: oscillating arm,        5: spindle, 501: bearing, 502: bearing, 51: tool mounting part,        511: recess, 513: inclined surface, 515: recess, 57: spring        receiving member, 60: clamping mechanism, 61: clamp shaft, 611:        shaft part, 612: groove part, 615: clamp head, 65: clamp spring,        67: push-down mechanism, 671: push-down sleeve, 673:        large-diameter part, 674: lower end surface, 675: biasing        spring, 676: spring receiving member, 7: lock mechanism, 71:        clamp member, 717: ridge part, 718: elastic ring, 73: holder,        731: insertion hole, 733: holding recess, 735: spring receiving        part, 737: abutment part, 75: collar, 751: bearing, 753: groove,        77, 770: lever, 771: arm, 772; engagement part, 773 circular        plate part, 774 cylindrical part, 775: projection, 776: inner        flange, 777: outside surface, 778: inside surface, 779: grip        part, 78, 780: rotary shaft, 781: eccentric part, 783:        engagement groove, 801: inlet, 803, 804, 805: inlet, 807:        outlet, 809: outlet, 81: partition, 83: closing member, 91: tool        accessory, 911: protruding part, 913: inclined surface, 93:        battery, A1: driving axis, A2: rotational axis, A3: rotational        axis, P: oscillation plane

1.-20. (canceled)
 21. A power tool configured to drive a tool accessoryin an oscillating manner, the power tool comprising: a motor; a spindlesupported to be rotatable around a driving axis and configured topivotally oscillate the tool accessory, which is removably mounted onthe spindle, using power generated by the motor; an inner housing thathouses the motor and the spindle and that has at least one airflow inletand at least one airflow outlet; an outer housing that houses the innerhousing and is elastically connected to the inner housing via at leastone elastic member to be movable relative to the inner housing; and apartition disposed between the at least one airflow inlet and the atleast one airflow outlet, the partition dividing a space defined betweenthe inner housing and the outer housing into a first airflow space and asecond airflow space, wherein the at least one airflow outlet isdisposed in the first airflow space and the at least one airflow inletis disposed in the second airflow space.
 22. The power tool as definedin claim 21, wherein the partition is attached to the inner housing. 23.The power tool as defined in claim 21, wherein the partition isintegrally formed with the inner housing.
 24. The power tool as definedin claim 21, wherein the partition is formed of an elastic elementconfigured to deform under pressure.
 25. The power tool as defined inclaim 21, wherein: the motor has an output shaft, and the spindle andthe motor are arranged such that the driving axis and a rotational axisof the output shaft extend in parallel to each other.
 26. The power toolas defined in claim 21, wherein: the inner housing is formed byconnecting a plurality of members, the power tool further comprises aclosing member that at least partly closes a gap between the pluralityof members.
 27. The power tool as defined in claim 26, wherein both ofthe partition and the closing member are integrally formed with eitherthe inner housing or the outer housing.
 28. The power tool as defined inclaim 26, wherein both of the partition and the closing member areintegrally formed with the inner housing.
 29. The power tool as definedin claim 28, wherein the partition and the closing member are eachformed of an elastic element.
 30. The power tool as defined in claim 21,wherein: the inner housing includes (i) a first end part that houses atleast the spindle, and (ii) a cylindrical part that extends in alongitudinal direction of the outer housing and that has an open end anda connecting end connected to the first end part, the at least oneairflow outlet is formed in the first end part, and the at least oneairflow inlet includes at least one of a first opening of the open endof the cylindrical part and a second opening formed in a peripheral wallthat defines the cylindrical part.
 31. The power tool as defined inclaim 30, wherein the partition is a tubular elastic element that isdisposed around the cylindrical part of the inner housing.
 32. The powertool as defined in claim 31, wherein the partition is integrally formedwith the cylindrical part of the inner housing.
 33. The power tool asdefined in claim 32, wherein the partition is configured to deform underpressure.
 34. The power tool as defined in claim 33, wherein: the motorhas an output shaft, and the spindle and the motor are arranged suchthat the driving axis and a rotational axis of the output shaft extendin parallel to each other.
 35. The power tool as defined in claim 23,wherein the partition is formed of an elastic element configured todeform under pressure.
 36. The power tool as defined in claim 35,wherein: the motor has an output shaft, and the spindle and the motorare arranged such that the driving axis and a rotational axis of theoutput shaft extend in parallel to each other.
 37. The power tool asdefined in claim 36, wherein: the inner housing is formed by connectinga plurality of members, the power tool further comprises a closingmember that is formed of an elastic element and integrally formed withthe inner housing, and the closing member at least partly closes a gapbetween the plurality of members.
 38. The power tool as defined in claim37, wherein the partition is formed of an elastically deformableelastomer.
 39. The power tool as defined in claim 21, wherein thepartition is formed of an elastically deformable elastomer and has atubular tapered shape that increases in circumference in a directionfrom a rear of the power tool towards a front of the power tool.
 40. Thepower tool as defined in claim 39, wherein: the power tool is anoscillating multi-tool having an elongated handle, at least one of thefirst and second airflow spaces being disposed inside the elongatedhandle, the partition is integrally formed with the inner housing, theinner housing includes (i) a first end part that houses at least thespindle, and (ii) a cylindrical part that extends in a longitudinaldirection of the outer housing and that has an open end and a connectingend connected to the first end part, the at least one airflow outlet isformed in the first end part, the at least one airflow inlet includes atleast one of a first opening of the open end of the cylindrical part anda second opening formed in a peripheral wall that defines thecylindrical part, and the partition surrounds the cylindrical part ofthe inner housing.